A Ping-Pong ball, nearly as light as a penny, rescued Wally Green. It sent him to China, Japan and North Korea. It took him to a nightclub in Hong Kong where, amid a whoosh of theater smoke and razzle-dazzle lights, a pool table was plucked from the floor and suspended in midair to make way for an exhibition Ping-Pong match.

A Ping-Pong ball transported Green from public housing projects in Brooklyn and dropped him in Midtown Manhattan. In a rec hall on 50th St., as a high school student contemptuous of the sport — was it even a sport, he used to think, this interplay between brittle ball and paddle? — he played against some of the city’s best, recently minted Americans from Guyana and China, Israel and Jamaica. He turned pro, with Rockstar Games, the maker of the Grand Theft Auto video game series, as his sponsor. He toured the world.

“No joke,” Green said. “If it wasn’t for table tennis, I’d be dead or in jail by now.”

Today, Green, 41, travels the country delivering inspirational speeches at colleges and wellness retreats. Last month, he encouraged young people to persevere during a TEDx talk. In June, he will give a graduation address at a charter school in Brooklyn. He tried out for The Cube, the TV game show hosted by the retired basketball star Dwyane Wade, partnering with a table tennis player born in Togo. He teaches at a Ping-Pong social club, the domain of Wall Street traders and others who can afford $49-an-hour table tennis sessions and $15 cocktails.

Green has rapped in Tokyo, danced hip-hop in Beijing and coached in Israel. He likes to use his iPhone as a paddle.

At a time when the pandemic has encouraged countries to turn inward, allowing xenophobia and prejudice to flourish, he is using table tennis, with a table 9-feet long and 5-feet wide, as a common ground.

Green is American, which made him an anomaly on the international table tennis circuit, and Black, which is even rarer. Asians dominate the upper echelons of global table tennis, most notably Chinese players. He has seen racism directed all around.

As the coronavirus spread from China and sparked deadly anti-Asian violence in the United States, Green went on TikTok to demand better of Americans. He has defended Eileen Gu, the California-born freeskier who drew criticism from some Americans when she won three medals for China at the Beijing Olympics.

“It’s so stupid, harassing someone to choose nationalities, when they are both,” he said.

Green’s wife is Japanese, and he said he is proud that their son is what he refers to as “a both.” Table tennis is filled with Olympians whose national allegiances have shifted throughout their careers, from China to Australia or Brazil, for example, or from Germany to Slovakia.

Table tennis once brought China and the United States together, he said. In 1971, an American table tennis squad arrived in Beijing, the first U.S. delegation to go since China’s Communist revolution in 1949. The effort was called Ping-Pong diplomacy and paved the way for the resumption of bilateral ties. When he played at the Pyongyang Open in North Korea in 2015, that same spirit of adventure and camaraderie animated Green.

And it’s what keeps him coming back, day after day, to Bryant Park, in Midtown Manhattan, where two tables under shade trees play host to pickup Ping-Pong games in a democratizing mash-up of cultures and incomes. Within a couple hours on one afternoon, the tables attracted a shirtless actor, an employee of a Japanese bookstore on his lunch break, a retiree in sandals, a doctoral student, a mother with a napping child in a stroller, and the brother of the head coach of the Milwaukee Bucks.

“This is the sport of love,” Green said. “You want to win so bad, but you’re there because you love it. You love Ping-Pong.”

An escape

A patch of lawn, part of a recent beautifying effort, was losing ground to dirt and dust. At a nearby playground, the slide ended in a corroded mess and rust had eaten at the links of a climbing dome. No one played.

Sitting on a bench near the stoop of his old apartment building in Marlboro Houses, one of the low-income housing projects in Brooklyn where he grew up, Green was nervous, his legs jiggling up and down.

“A lot went down here,” he said. “I lived a lot of life here.”

In December, a man was shot and killed just outside Green’s former home in a crumbling complex with years of backlogged complaints from residents. There were three other killings at Marlboro Houses last year.

When he was at Lafayette High School, where less than half the students graduated on time if ever, Green played basketball, football and volleyball. He wrestled. Lafayette produced more than a dozen Major League Baseball players, and sports were meant to keep Green out of trouble.

But trouble was all around him, he said: guns, gangs, “whuppings at home” and on the stoop and just out of eyesight of the police who patrolled the projects. In the early 1980s, a Black subway worker in the neighborhood was beaten to death by a mob of white men in what authorities said was a racially motivated attack.

His gang name was Tragedy because his mother and stepfather said that was what followed Wally Green. Twice, he was grazed by bullets, he said. A close friend was shot next to him during a drive-by but survived. Green’s juvenile rap sheet — shoplifting, weapons possession, carjacking — was long and earned nights at Rikers Island and the Brooklyn House of Detention.

Green’s father, who was born in Nigeria, tried to straighten out his son by sending him to boarding school there. Without his gang, without the bravado of the projects, Green was beaten and bullied, he said. Returning to New York was one of the happiest moments of his life.

Green remembers Asian American students at Lafayette High playing Ping-Pong in the lunchroom, their shorts worn unfashionably high.

“I made fun of them like crazy,” he said. “I feel bad about that now.”

Tensions heightened in the years after Green finished high school. In just one year, 2002, more than two dozen Asian students were assaulted or harassed at Lafayette, a government investigation concluded. The school was found to be failing in other ways, too, and was closed eight years later.

A chance encounter at a pool hall brought table tennis into Green’s life. Following a fight at the pool table, he vented his frustration by playing a point on a nearby Ping-Pong table that was the domain of Asian athletes. He swung with an exaggerated kung fu chop, and the ball nicked the table, spinning away from any return.

His opponent was impressed, if not necessarily appreciative of the culturally demeaning antics, and directed Green to a rec hall in Midtown. At rows of tables, players, mostly from the Caribbean, practiced, the air syncopated with the pop-pop-pop of plastic balls.

“I didn’t know Black kids played Ping-Pong,” Green said. “I didn’t know dope kids played.”

A man there mentored Green, even when a handgun accidentally tumbled out of his backpack. The mentor paid for Green to train at a sports academy in Hanover, Germany. He was 19 years old, and the anger that animated his childhood started to dissipate, he said.

“I was tight, I was tough,” Green said. “I had to get rid of all that negative energy.”

In 2001, he turned pro and began playing international tournaments. Green lost a lot, but in a sport with a staid reputation, he brought charisma and showmanship. T.V. crews gravitated toward him. Rockstar Games, which made a table tennis video game, sponsored his travel on the pro tour. He befriended some of the world’s best table-tennis stars.

“Everyone knew Wally Green,” he said.

An equalizer sport

Every name of the sport diminishes it. Ping-Pong, a trademarked name, evokes a suburban garage or a college dorm with plastic cups of beer. Table tennis make it sounds like a real sport that has been miniaturized and shorn of seriousness. Whiff-whaff, as the pastime was sometimes known in 19th century Britain, where gentlemen used cigar boxes to hit a whittled champagne cork, is just silly.

Whatever it’s called, it’s an equalizer sport. No particular physical build confers great advantage, and there is little need for expensive equipment. Quicksilver reflexes, pinpoint accuracy and an ability to calculate chess-like moves in split seconds are vital.

Some of the sport’s most accomplished athletes in the United States are immigrants or children of immigrants. The top ranks of American table tennis have featured players born in China, Belgium, Egypt, Thailand, Vietnam, Iran, South Korea, Romania and the former Yugoslavia. There are more American paddlers of Asian heritage than in any other Olympic sport.

Chinese athletes have emigrated to nations on six continents and represented them at the Olympics; one of the oldest players at the Tokyo Games last year was a 58-year-old woman born in China who played for Luxembourg.

When Green started playing seriously, he discovered that the center of gravity in table tennis is Asia. In China, there are entire sports academies dedicated to table tennis. There is a professional league. The Chinese team swept every gold medal at the last Summer Olympics, save one, which was won by a Japanese mixed doubles pair.

The highest-ranking American in men’s singles is Kanak Jha, at No. 32. The next best American is No. 165. (The American table tennis squad at the Tokyo Olympics was entirely Asian American.)

Tournaments first took Green to Asia, and he stayed for months at a time, cobbling together different income streams to afford daily life. In South Korea, he trained briefly with the men’s national team, watching as the women’s team would bow when the male athletes entered the room.

In Japan, people expected him to rap because of his race, he said, so during a tough financial period, he obliged. He married a Japanese pop singer, and they now live in Harlem.

In China, if he was short of cash between tournaments, he would visit a gym, where locals would invariably direct him to the basketball courts. He’d ask to play Ping-Pong and would allow himself a loss. Then he’d put some money on the table and request someone better. He’d lose again. Then he would demand an even better player, double or nothing. That time, he’d win.

“It was my China hustle,” Green said.

Back in New York, table tennis was becoming a thing, something that hipsters had decided to reclaim from suburban basements and dank rec centers. A pair of filmmakers threw what they called “naked” Ping-Pong parties. There was no nudity involved, but the name was a lure.

Among the star attractions was Green, who played exhibition matches with Kazuyuki Yokoyama, a Japan-born former software executive who likes to play in sequined boxers and the occasional feather boa.

Soon, the crowds overflowed from the film producers’ Tribeca loft. In 2009, Spin, a Ping-Pong social club with mood lighting and a lounge vibe, was born. There are now eight outlets in North America.

“It’s kind of a dorky sport,” said Franck Raharinosy, one of Spin’s co-founders, whose parents are from Madagascar and France. “Wally, from the moment you saw him, he was different. He was cool.”

Susan Sarandon, the actor, joined the New York table tennis community. She, too, added glamour. At the Shanghai International Film Festival in 2011, she brought along Green for a stroll down the red carpet.

“Wally is a very New York person,” said Yokoyama, his exhibition partner. “But he’s at home everywhere in the world.”

Ping-Pong diplomacy

In 2015, Green was scanning the list of upcoming tournaments and saw mention of the inaugural Pyongyang Open. Two years before, Dennis Rodman, the American basketball star, had gone to North Korea for the first of several trips and palled around with Kim Jong-un, the heir to the insular nation’s dictatorial dynasty. Rodman called his trip “basketball diplomacy,” and Green figured he would try for the original Ping-Pong version.

He was the only American at the Pyongyang Open. When he played a North Korean opponent, the crowd reacted in ecstatic unison to each of Green’s misses. The event felt like a Cold War proxy battle, Green said, but instead of getting angry, he hammed it up for the audience and coaxed laughs out of crowds. He didn’t even mind, he said, when he lost, and he hugged the victor.

“I wanted to do my own Ping-Pong diplomacy, bring world peace, spread the love,” Green said. “I wanted the North Koreans to realize that Americans aren’t their enemies.”

He has traveled the world — and his own country — enough to see plenty of prejudice. In Croatia, he waved back at a shaven-headed man, only to realize the man was flinging a Nazi salute at him. In China, a man shook Green’s hand and then looked at his own to see if the American’s skin tone had transferred.

“I’ve met people who are ignorant and people who are brainwashed, like in North Korea, but I don’t hold that against them,” he said.

When anti-Asian violence surged following the pandemic, he posted on TikTok that “Asians are NOT the virus,” earning more than 817,000 views. Some commenters asked why he was sticking up for Asians when they weren’t his people. During Pride month, he posted support of the L.G.B.T.Q. community.

“We’re all one human race,” he said.

Back when he began playing table tennis in Midtown, Green got to know a courtly, older athlete named George Braithwaite. Born in Guyana, Braithwaite moved to New York to work for the United Nations and won multiple table tennis U.S. Opens.

Only years later did Green discover that Braithwaite was the only Black member of the American table tennis delegation that went to Beijing in 1971. Braithwaite died of Covid-19 in 2020.

For years, Green and Braithwaite would top off a night of Ping-Pong with a feast of oxtails and potatoes at Chen’s Food Court, a restaurant owned by Robert Chen. Table tennis was Chen’s salve after Sept. 11, 2001, when he loaded a wheelbarrow with water bottles for the firefighters at the fallen Twin Towers.

Last fall, Chen, who was born in southern China, opened a new table tennis club in Queens. On a recent evening, after coaching a retired radiation physicist and a fund-raising officer at Spin, Green and Yokoyama, his exhibition match partner with a penchant for minimal clothing, went to check it out.

They climbed to the darkened second floor of a building under construction, sawdust in the air and insulation exposed. Staccato bursts of careening table tennis balls emanated from behind a plywood wall.

Inside, Chen presided from a fold-up metal chair.

“You came, Wally,” he said, grinning, “all the way to Queens.”

Training that night at the new club was Yezen Braick, a high-school student from Brooklyn whose mother brings him to train more than an hour away because her son has that gift. The family came from Syria, sought refuge in Canada, where Yezen lived as a small child, and settled in New York.

“I’m going to the Olympics,” he said, with a teenager’s confidence. “I’ve got a plan. If I don’t make the American team, then I’ll play for Canada.”

Green and Yokoyama picked up their paddles. The ball ricocheted with lightning geometry. Green wiped the sweat off his brow. Yokoyama removed a shirt.

The clock edged near midnight. It was time to go home.

“Just one more,” Green said. “Just one more.”