Born in rural Carrabelle, Florida, Buck O’Neil was initially denied the opportunity to attend high school due to racial segregation; at the time, Florida had only four high schools specifically for African Americans. However, after working a summer in a celery field with his father, O’Neil left home to live with relatives and attend Edward Waters College in Jacksonville, where he completed high school and two years of college courses. He left Florida in 1934 for several years of semi-professional “barnstorming” experiences (playing interracial exhibition games). The effort paid off, and in 1937, O’Neil signed with the Memphis Red Sox for their first year of play in the newly formed Negro American League. His contract was sold to the Monarchs the following year. Buck O’Neil had a career batting average of .288 between 1937 and 1950, including five .300-plus seasons at the plate, as well as five seasons in which he did not top .260. In 1946, the first baseman led the NAL with a .350 batting average and followed that in 1947 with a .305 mark in 16 games. He also posted averages of .344 in 1940 and .330 in 1949. He played in four East-West All-Star Games in three different seasons and two Negro World Series. A World War II tour in the U.S. Navy from 1943–1945 briefly interrupted his playing career.

Buck O’Neil was named manager of the Monarchs in 1948 after Frank Duncan’s retirement, and continued to play first base as well as a regular through 1951, dropping to part-time status afterward. He managed the Monarchs for eight seasons from 1948 through 1955 during the declining years of the Negro leagues, winning two league titles and a shared title in which no playoff was held during that period. His two undisputed pennants were won in 1953 and 1955, when the league had shrunk to fewer than six teams. On August 5, 2006, Buck O’Neil was admitted to a Kansas City hospital after complaining that he didn’t feel well. He was admitted for fatigue and was released three days later only to be re-admitted September 17. On September 28, Kansas City media reported that O’Neil’s condition had worsened. On October 6, O’Neil died at the age of 94 of heart failure and bone marrow cancer.