Henry Louis Aaron (February 5, 1934 – January 22, 2021), nicknamed "Hammer" or "Hammerin' Hank," was an American Major League Baseball (MLB) right fielder. He played 21 seasons for the Milwaukee/Atlanta Braves in the National League (NL) and two seasons for the Milwaukee Brewers in the American League (AL), from 1954 through 1976. Aaron held the MLB record for career home runs for 33 years, and he still holds several MLB offensive records. He hit 24 or more home runs every year from 1955 through 1973, and is one of only two players to hit 30 or more home runs in a season at least fifteen times. In 1999, The Sporting News ranked Aaron fifth on its "100 Greatest Baseball Players" list. He also later served as the senior vice president of the Atlanta Braves.

Aaron holds the MLB records for the most career runs batted in (RBIs) (2,297), extra base hits (1,477), and total bases (6,856). The total base record is remarkable in context: at the time of his retirement, he had travelled over 12 miles farther on the base paths than any other player in MLB history. Aaron is also third all-time for career hits (3,771) and fifth in runs scored (2,174). He is one of only four players to have at least 17 seasons with 150 or more hits. Aaron's ability as a hitter can be illustrated by his still having over 3,000 hits even without counting any of his home runs.

Aaron was born and raised in and around Mobile, Alabama. Aaron had seven siblings, including Tommie Aaron, who played major-league baseball with him. He appeared briefly in the Negro American League and in minor league baseball before starting his major league career. By his final MLB season, Aaron was the last former Negro league baseball player on a major league roster. During his time in Major League Baseball, and especially during his run for the home run record, Aaron and his family endured extensive racist threats. His experiences fueled his activism during the civil rights movement.

Aaron played the vast majority of his MLB games in right field, though he appeared at several other infield and outfield positions. In his last two seasons, he was primarily a designated hitter. He was an NL All-Star for 20 seasons and an AL All-Star for one season, and he holds the record for the most All-Star selections (25), while sharing the record for most All-Star Games played (24) with Willie Mays and Stan Musial. He was a three-time Gold Glove winner, and in 1957, he won the NL Most Valuable Player (MVP) Award when the Milwaukee Braves won the World Series.

Aaron was born in Mobile, Alabama, to Herbert Aaron Sr. and Estella (Pritchett) Aaron. He had seven siblings. Tommie Aaron, one of his brothers, also went on to play Major League Baseball. By the time Aaron retired, he and his brother held the record for most career home runs by a pair of siblings (768). They were also the first siblings to appear in a League Championship Series as teammates.

While he was born in a section of Mobile referred to as "Down the Bay", he spent most of his youth in Toulminville. Aaron grew up in a poor family. His family could not afford baseball equipment, so he practiced by hitting bottle caps with sticks. He would create his own bats and balls out of materials he found on the streets. His boyhood idol was baseball star Jackie Robinson. Aaron attended Central High School as a freshman and a sophomore. Like most high schools, they did not have organized baseball, so he played outfield and third base for the Mobile Black Bears, a semipro team. Aaron was a member of the Boy Scouts of America.