BEIJING — Forty years ago this month, on a cold, gray morning, President Richard Nixon arrived here on a groundbreaking visit aimed at improving relations with China after decades of hostility. He stepped off Air Force One and shook hands with the Chinese prime minister, Zhou Enlai.

A photograph that captures the moment also shows a tall, bespectacled Chinese interpreter standing on the tarmac, just behind Zhou. That man is Ji Chaozhu.

“I remember that day clearly,” Ji, now 82 and retired, said a few weeks ago at his apartment on the southern island of Hainan. “Premier Zhou told me just to stand right behind him and listen clearly.”

Ji was also at Zhou’s side in Geneva, in 1954, when Secretary of State John Foster Dulles famously refused to shake hands with his Chinese counterpart, a slight that deepened strains after the Korean War.

There was, in fact, a Zelig-like quality to Ji’s life. Because he served for more than 20 years as an English-speaking interpreter for China’s leaders, Ji turns up in numerous historic photographs: on the Tiananmen rostrum in 1971 with Chairman Mao Zedong and the American journalist Edgar Snow (a subtle hint that China sought improved relations with the United States); with Mao and his last official visitor, Prime Minister Zulfikar Ali Bhutto of Pakistan, in 1976; and helping Deng Xiaoping don a white cowboy hat during his whirlwind tour of the U.S. in 1979, which included a visit to a Texas rodeo.

Historians say Ji did not make policy. But his language skills helped shape negotiations during one of the most important diplomatic missions of the past half-century.

Declassified White House documents list him as a participant in most of the key meetings Nixon and Henry Kissinger held with Chinese leaders in the early 1970s, including those that took place during Kissinger’s secret visit to China in July 1971.

Ji’s story is all the more remarkable because of his childhood ties to the United States. He grew up in New York City, attended Harvard and then dropped out of college to return to China in 1950, shortly after the victory of Mao’s forces, hoping to help build a Communist paradise.

He attended talks that ended the Korean War and worked in China’s leadership compound in Beijing, making him a witness to the intrigue and power struggles that raged there during the 1960s and 1970s.

Today, Ji divides his time between Beijing and a winter home on Hainan. His memory has faded. But he remains proud of the role he played in Chinese-American relations.

“I wanted these two great countries to be at peace,” he said. “These were the two I had a connection to.”

Interpreters for world leaders rarely tell their stories. But four years ago, after meeting the American hedge fund billionaire Ray Dalio, who urged him to write his memoirs, Ji published “The Man on Mao’s Right,” an account of his life as an interpreter and diplomat.

The story he told was compelling.

Ji was born in 1929, into a wealthy family in the northern Chinese province of Shanxi. In the late 1930s, his family fled south before the invading Japanese and then left for the United States on the advice of Zhou Enlai, then a young Communist revolutionary.

The family returned to China after the Communist victory with the help of his elder brother, Ji Chaoding, a high-ranking underground Communist.

“When the Korean War broke out, I was torn between my love for two countries,” he said. “But I knew I was fundamentally Chinese.”

Back in China, Ji enrolled at Tsinghua University, and was then selected as an interpreter at the talks that led to a cease-fire in the Korean War.

Soon after, he joined the Ministry of Foreign Affairs, and over the next 30 years served as a translator for China’s leaders, including Mao (“He complained I spoke too loudly when I translated”); Zhou (“He was like a father”); Jiang Qing, Mao’s wife and a member of the infamous Gang of Four during the Cultural Revolution (“She was the horror of all horrors!”); and Deng (“He was so short, I had to spread my legs to get lower when I interpreted.”)

In those years of isolation from the West, Ji bicycled to work, earned about $10 a month and had but one blue Mao suit.

He was also one of only a handful of trustworthy and competent English-speaking interpreters in China. Another was his younger colleague Tang Wensheng, or Nancy Tang, Mao’s primary interpreter during the Nixon and Kissinger visits.

Ji said he had recommended Tang, who had been a family friend in New York. In the 1940s, their fathers had started a Chinese-language newspaper together.

When Kissinger and Nixon visited in the early 1970s, Ji and Tang served as the chief interpreters. The U.S. delegation usually came without its own interpreters.

“Nixon really didn’t trust the State Department to keep a secret, so we didn’t really have anyone of our own,” Winston Lord, an aide who traveled with Kissinger and Nixon to Beijing, said in an interview.

But shortly after that historic moment, Ji and Tang were drawn into the power struggles of the Cultural Revolution, which spanned the years from 1966 to 1976. Mao, in his latter years, grew suspicious of everyone around him, including Zhou Enlai. Historians say Mao’s close advisers, including Tang, struggled with Zhou and his associates.

Because of his ties to Zhou, Ji was banished from the Foreign Ministry just months after Nixon’s visit. He was sent to the countryside, to do hard labor. He ended up planting rice and hauling manure.

“The Cultural Revolution was a disaster,” he said. “Those were the darkest days of the People’s Republic.”

Tang declined to be interviewed for this article. But she suffered after Mao died and the Gang of Four fell from power, in 1976.

Ji was rehabilitated in 1972, when Zhou asked: “Where has Little Ji gone? I need him!” He was sent to the countryside again, and then back to the leadership compound, part of the bizarre power struggles that shook the leadership compound in the Mao era.

After Mao’s death, Ji accompanied Deng Xiaoping on his trip to America in 1979, and over the years met Presidents Jimmy Carter, Ronald Reagan and George Bush. He was named China’s ambassador to Fiji and to Britain, and even served as an undersecretary general at the United Nations.

It was all part of his peculiar journey: raised in the United States, representing China, but never entirely comfortable in Beijing.

To this day, Ji insists that he speaks poor Chinese and can barely write decent Chinese characters. Still, he says he has no regrets, and has never lost faith in the Communist Party. But, with his memory failing and his language muddled, his wife, Wang Xiangtong — also an interpreter — steps in, to interpret the gestures and thoughts of a master interpreter.

“Let’s just say we’re survivors,” she said. “That’s what he’s trying to say.”