Jackie Robinson became the first African American to play in the Major Leagues on April 15, 1947, when he took the field in the top of the first inning against the Boston Braves. When Robinson took his spot at first base, he broke baseball’s six-decade-long color barrier, which not only made him an icon to those fighting for racial equality but also a target for those who sought to fight against it. Jackie’s poise and strength—both on and off the field—are why we still honor him today.

Robinson’s narrative doesn’t begin and end with that one April afternoon in Boston. His legacy was built as both an athlete and an activist over the course of his entire life.

In 1938, at Pasadena Junior College, he wasn’t just breaking records on the field (including the school record in the broad jump, which was previously held by his 1936 Olympic medal-winning brother, Mack). He was also standing up for the rights of his friends, as evidenced by his January 1938 arrest after speaking out when he felt the police were unlawfully holding an African American friend of his.

After Pasadena, he enrolled at the University of California Los Angeles (UCLA), where he became the first athlete in school history to letter in four sports (track and field, football, basketball and baseball). Jackie left UCLA after the 1940 football season, just shy of graduation. After a couple of seasons playing semi-pro football—the NFL wouldn’t be integrated until 1946, when Jackie’s UCLA teammate, Kenny Washington, signed with the Los Angeles Rams—Jackie was drafted into the United States Army.

With his college education, and high marks in marksmanship and character, Jackie seemed a shoo-in for Officers’ Candidate School, but his application, along with those of several other Black applicants, was rejected. Jackie turned to his friend, and fellow resident at Fort Riley in Kansas, heavyweight boxing champion Joe Louis. Although Louis wasn’t an officer, he wielded some power at Fort Riley, and within a few weeks, Jackie and the other applicants were accepted into the OCS.

Robinson’s commitment to fighting inequality nearly got him court-martialed. In 1944, he was riding in a U.S. Army bus with the wife of a fellow Black officer. The driver, believing the light-skinned woman to be white, ordered Robinson to the back of the bus. Robinson, noting the fact that U.S. Army buses were not segregated, refused. The driver backed down but called Military Police after the ride. Robinson was taken into custody and eventually charged with insubordination, disturbing the peace and drunkenness (although he neither drank nor smoked). He fought back and, despite false witness statements stacking the deck against him, he was eventually found not guilty.

Jackie was discharged later that year, and by 1945 had returned to baseball, signing with the Kansas City Monarchs of the Negro American League. Word of his play soon reached Dodgers’ owner Branch Rickey, who decided the speedy infielder who could out-hit most of the players in the league would be the one to break the color barrier.

While becoming the first African American player in the majors could have been his legacy on its own, Robinson made sure that he wasn’t just a name in a box score that one time in 1947. He starred for the Dodgers, winning the 1947 Rookie of the Year Award, and helping Brooklyn reach the World Series (they lost to the New York Yankees). That year, as per an agreement with Rickey, he also learned how to fight back without fighting. Rather than react to the constant racial abuse from fans and other teams alike, Jackie used unfathomable restraint and poise, turning the other cheek so as not to give his detractors any reason to end Rickey’s “experiment.”

In 1949, and with Rickey’s restrictions on fighting back lifted, Jackie won the National League Most Valuable Player Award and led the Dodgers to another World Series. Robinson would also help the Dodgers to another World Series, and another loss to the Yankees. In 1955, with two more World Series losses to the Yankees sprinkled in along the way, Robinson finally helped the Dodgers beat the Yankees in the Fall Classic, adding World Champion to his list of many accomplishments. He retired in 1956 (after another World Series loss to the cross-town rivals in the Bronx), and was elected to the Major League Baseball Hall of Fame in 1962, becoming the first African American Hall-of-Famer.

His accomplishments didn’t end there. His post-career achievements included becoming the first-ever African American to serve as VP of a major American corporation (Chock full o’Nuts from 1957-1964), becoming the first African American commentator for Major League Baseball (1972) and he was on the board of the NAACP, where he continued his fight for Civil Rights and equality.

Robinson’s words continue to influence today’s activist athletes, too. In his 1972 autobiography, he said: “I cannot stand and sing the anthem. I cannot salute the flag; I know that I am a black man in a white world.” These are words that professional athletes like Colin Kaepernick used as inspiration for their own controversial anthem protests during NFL games in 2017.

Jackie Robinson wasn’t just a Hall of Fame baseball player, he truly was a Hall of Fame person.

In June of 1972, just a few months prior to his death, the Dodgers retired Jackie’s number 42. In 1997—the 50th anniversary of Jackie’s first game—his number was retired by Major League Baseball, meaning it would no longer be issued to any new players. Those who were already using the number were allowed to keep it (the last player to wear it was the Yankees’ Mariano Rivera, who retired in 2013).

Starting in 2004, MLB officially began recognizing April 15 as Jackie Robinson Day, taking time to honor Robinson’s life and legacy on the field prior to every game. In 2007, Ken Griffey, Jr.—one of the biggest stars in baseball at the time—asked the Commissioner’s office for special permission to wear 42 on Jackie Robinson Day, to honor Robinson further. Commissioner Bud Selig loved the idea so much, other teams were encouraged to allow players to don the number as well. In 2009, every player, coach and even the umpires, wore 42 to honor Jackie, which is still the case today.

Starting in 2018, teams also began wearing a commemorative patch on their caps and sleeves, and socks with the number 42 on them on Jackie Robinson Day. All proceeds from merchandise sold go to the Jackie Robinson Foundation.