The eyes of Abraham Lincoln gazed down from a portrait on the paneled walls inside the executive offices of the Brooklyn Dodgers Baseball Club as Branch Rickey fire-hosed a torrent of racial slurs at Jackie Robinson. The president and general manager of the Dodgers had little doubt that the young ballplayer on the other side of his mahogany desk had the bat, glove and speed to make it in the big leagues, but temperament—not talent—was the point of this evaluation on August 28, 1945. Rickey needed to know whether this grandson of a slave and son of a sharecropper could absorb the abuse that would await as the 20th century’s first African American major leaguer.

For three hours, Rickey role-played countless scenarios in which the Negro Leaguer might encounter racial hostility on and off the field to see how he would handle it. “They’ll taunt you and goad you,” Rickey warned. “They’ll do anything to make you react. They’ll try to provoke a race riot in the ballpark. This is the way to prove to the public that a Negro should not be allowed in the major leagues.”

“Mr. Rickey, are you looking for a Negro who is afraid to fight back?” asked the young diamond star.

“Robinson, I’m looking for a ballplayer with guts enough not to fight back,” explained Rickey.

“Mr. Rickey, if you want to take this gamble, I will promise you there will be no incident,” Robinson assured the Dodgers executive before agreeing to a contract with the organization. Both men knew the gamble was a big one because—contrary to the mythology that subsequently developed around him—Robinson wasn’t the turn-the-other-cheek type.

The Hall of Famer wrote in his 1972 autobiography “Never Had It Made” that he had “believed in payback, retaliation” from the time he was 8 years old and a neighborhood girl called him the vilest of racial epithets. “Jackie had a genius for getting into extra-curricular scrapes,” wrote sports columnist Will Connolly, and he was quick to speak out against injustice. While in the Army in 1944, the defiant Robinson had been arrested for insubordination after refusing to sit in the back of a military bus as ordered by the driver. He was temperamental, too quick-tempered some teammates feared. He talked back to white officials, struck back against white players who levied hard blows. Rickey had heard the reports that Robinson was a “racial agitator” but believed he would have been considered “a competitor” had his skin tone been paler.

After breaking baseball’s color barrier on April 15, 1947, the rookie kept his promise—even when opposing players spiked him in the thigh or pitched beanballs at his head, even when he received hate mail and death threats, even when he was forced to shower separately from his white teammates, even when bigoted fans hurled invectives—and worse—at him.

Robinson faced perhaps his greatest test a week after his debut when the Philadelphia Phillies, led by their manager Ben Chapman, sprayed the field with racial taunts and calls for him to “go back to the cotton fields.” Robinson daydreamed “for one wild and rage-crazed minute” about “what a glorious, cleansing thing it would be to let go. To hell with the image of the patient black freak I was supposed to create. I could throw down my bat, stride over to the Phillies dugout, grab one of those white sons of bitches and smash his teeth in with my despised black fist.” Knowing that he carried the prospects of an entire race, though, Robinson endured it all without retaliating, and it ate him alive. He suffered from stomach pains. His hair turned gray prematurely.

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Before the start of Robinson’s third season in 1949, Rickey called his new star into his office and issued what he called “an emancipation proclamation.” Rickey told a relieved Robinson he no longer needed to restrain himself. “You can be yourself now,” he said.

With his cheek no longer turned, Robinson started to challenge other players and argue with umpires. Some fans and sportswriters began to turn on the Dodgers star as a result. The Sporting News called him “a chronic griper” and took him to task for “umpire-baiting.” No longer the “martyred hero,” he was labeled a “troublemaker,” “uppity” and a “rabble-rouser.”

What he really was, however, was the true Jackie Robinson, someone who would speak out, someone who would fight back. “If I had a room jammed with trophies, awards and citations, and a child of mine came into that room and asked what I had done in defense of black people and decent whites fighting for freedom, and I had to tell that child that I had kept quiet, that I had been timid, I would have to mark myself a total failure at the whole business of living,” Robinson wrote.

When his playing days came to an end after the 1956 season, Robinson continued to be an outspoken civil rights crusader off the field. For more than a decade, he served on the board of the National Association for the Advancement of Colored People (NAACP) and raised money for the Southern Christian Leadership Conference (SCLC). In his weekly column in the New York Post, Robinson spoke out against bigotry inside and outside of baseball, and he help found the Freedom National Bank, a financial institution serving African Americans in Harlem who had struggled to get mortgages and business loans. He lobbied presidents and protested with Martin Luther King Jr., who called the baseball pioneer “a sit-inner before sit-ins, a freedom rider before freedom rides.” He also served as the first vice president of Operation PUSH (People United to Save Humanity), founded by his friend Reverend Jesse Jackson.

During the 1960s, Robinson wasn’t afraid to take positions that angered those inside the civil rights movement. Believing Democrat John F. Kennedy too timid on civil rights, he campaigned for Republican Richard Nixon during the 1960 presidential campaign only to pull his support eight years later. “He’s sold out,” Robinson said of Nixon’s courting of segregationists such as South Carolina Senator Strom Thurmond during the 1968 presidential campaign. “He’s prostituted himself to get the Southern vote.” Robinson also resigned from the NAACP’s board, believing it “unresponsive to the needs and aims of the black masses.”

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Although a widely admired figure today, Robinson took nearly identical political stances as some modern-day athletes who stir controversy. “I cannot stand and sing the anthem. I cannot salute the flag,” Robinson wrote in his 1972 autobiography. “I know that I am a black man in a white world. In 1972, in 1947, at my birth in 1919, I know that I never had it made.”

A quarter-century after breaking the color barrier, Robinson lamented the lack of racial equality in baseball. He criticized major league teams for failing to employ African Americans as managers, coaches and front-office executives. He agreed to throw out the first pitch before Game 2 of the 1972 World Series—but only if he wasn’t censored. “If you people expect me to change my thinking, or my speech, you’re mistaken because I’m simply not going to do it,” Robinson told a Major League Baseball executive.

Robinson was true to his word. “I am extremely proud and pleased to be here this afternoon,” he told the sellout crowd in Cincinnati and millions watching at home, “but must admit I’m going to be tremendously more pleased and more proud if I look at that third base coaching line one day and see a black face managing in baseball.”

Robinson wouldn’t get a chance to see that racial barrier fall, however, as he died nine days later. His last public appearance proved the true measure of a man not prone to bite his tongue.