For many Americans of the past century, there may have been no greater measure of individual achievement than baseball legend Babe Ruth’s career record of 714 home runs. On a spring night in 1974, Hank Aaron surpassed that mark — and struck a blow for civil rights in the US.

Aaron was an African-American man who was born in the segregated South at a time when blacks were barred from playing Major League Baseball. As he approached the record Ruth set in an all-white sport, Aaron was subjected to death threats and racist abuse so vicious he said it “carved a piece of my heart away”. When he hit his 715th home run in the home stadium of his Atlanta Braves, Aaron made more than sports history.

In the television broadcast of the game on April 8, 1974, announcer Vin Scully said: “What a marvellous moment for baseball. What a marvellous moment for Atlanta and the state of Georgia. What a marvellous moment for the country and the world. A black man is getting a standing ovation in the Deep South for breaking the record of an all-time baseball idol.”

Henry Louis “Hank” Aaron died on Friday at the age of 86, and was remembered both as one of the greatest players in the sport known as “America’s pastime” and as a hero of the US civil rights struggle.

“America lost an extraordinary soul,” Stacey Abrams, the Georgia political leader wrote on Twitter. “On the field, he brought power + purpose. In the community, Hank Aaron invested in progress, in people & in dreams.”

“His monumental achievements as a player were surpassed only by his dignity and integrity as a person,” said Rob Manfred, the commissioner of MLB who described his friendship with Aaron as “one of the greatest honours of my life”.

Aaron began his baseball career in the segregated Negro Leagues in the early 1950s before moving up to the majors. An all-around star, his trademark was consistency — over 23 seasons, he hit 755 home runs, a record that would stand for over three decades. He was inducted into the Baseball Hall of Fame in 1982.

It was his methodical pursuit of Ruth’s record that established Aaron as a civil rights icon. He received a torrent of hate mail from detractors who threatened to kill him if he surpassed the New York Yankees slugger.

That experience remained vivid for Aaron well into his retirement. In 2014 he told USA Today that he would recite from memory the threats he received “to remind myself that we are not that far removed from when I was chasing the record. If you think that, you are fooling yourself.”

Born one of eight children to a boilermaker’s assistant and tavern owner in Mobile, Alabama, Aaron was inspired to take up baseball after listening to a speech by Jackie Robinson, who in 1947 became the first black player in the major leagues.

Aaron joined the Negro Leagues’ Indianapolis Clowns in 1952 before making his major league debut with the Milwaukee Braves two years later. They won the World Series in 1957 and Aaron remained with the franchise through its move to Atlanta before ultimately retiring with the Milwaukee Brewers in 1976, two seasons after breaking the home run record.

For all his success, Aaron was often overshadowed during his career by more flamboyant stars who played in bigger cities — such as Mickey Mantle of the New York Yankees and Willie Mays of the New York and San Francisco Giants.

After his playing days, Aaron became one of the first black executives in the front offices of MLB, working for the Atlanta Braves. He also served on the president’s circle of the NAACP Foundation, the philanthropic arm of the prominent US civil rights organisation.

The boxer Muhammad Ali once said that Aaron was “the only man I idolise more than myself”.

In a 1995 interview with the Hartford Courant to promote a documentary of his career, Aaron reflected on the significance of his home run record, and why dethroning Ruth unsettled so many of his contemporaries.

“I kind of snuck up on them a little bit,” he said. “I was not the big glamour boy . . . from New York City. So my record, the hate mail that I got was not so much [a reaction] to the threat of what I was accomplishing, it was the threat of me being black and also not being a New York player.”