Early lifeJohnson was born in Snow Hill, Maryland, on October 26, 1899, to Annie and William Johnson. His family moved to Wilmington, Delaware, when he was five years old. He attended Howard High School but quit to work on the docks in New Jersey. Johnson was 5 feet, 11 inches tall and weighed 150 pounds.
Baseball careerIn 1919, Johnson played for a Philadelphia semi-pro team, the Madison Stars. He was acquired by a Negro major league club, the Hilldale Daisies, for $100, and played for Hilldale from 1921 to 1929. During that time, he was nicknamed "Judy" because he resembled Judy Gans, a player for the Chicago American Giants. Future Baseball Hall of Famer John Henry Lloyd became Johnson's mentor and taught him how to play third base.
In 1924, Johnson had a batting average of .327. Hilldale faced the Kansas City Monarchs that year in the first Negro World Series, and Johnson led all batters with a .364 average in a losing effort. The following year, Johnson batted .392, and Hilldale defeated Kansas City in that season's Negro World Series. In 1929, Johnson batted .416.
When the Hilldale club folded, Johnson became the player-manager of the Homestead Grays. There, he discovered and became a mentor to future Hall of Famer Josh Gibson. Johnson then ended his career playing for the Pittsburgh Crawfords from 1932 to 1936. He was the team's captain and helped them win the pennant in 1935. Johnson had a career batting average of .298 in the Negro major leagues.
After his playing career ended, Johnson was a coach and scout for several Major League Baseball teams; he signed Dick Allen. Johnson became the first black coach in the majors when he coached the Philadelphia Phillies in 1954.
LegacyJohnson was a good fielder, and he was considered one of the greatest third basemen of the Negro leagues. In 1975, he became the sixth black player inducted into the National Baseball Hall of Fame. He was also inducted into the Delaware Sports Museum and Hall of Fame and the Philadelphia Sports Hall of Fame. A statue of Johnson stands outside Frawley Stadium in Delaware.
Johnson was married to Anita Irons. The couple had one daughter, Loretta, who married major league player Bill Bruton. Johnson died on June 15, 1989, in Wilmington, Delaware.
The William Julius "Judy" Johnson House at Marshallton, Delaware was added to the National Register of Historic Places in 1995.