Stewart, a black player, was dominant in the American Tennis Association (ATA) during the 1940s and 1950s, along with Althea Gibson from the women's bracket.

[1] A seven-time singles champion, he won his first ATA title in 1947.

[2] In 1952 he and Reginald Weir were the first blacks to compete at the U.S. national championships (modern day US Open).

[3] A left-handed player, Stewart was a doubles silver medalist for Panama at the 1954 Central American and Caribbean Games in Mexico City and also represented his birth country at the Bolivarian Games.

[4] Stewart played collegiate tennis for South Carolina State University (then known as South Carolina State Agricultural and Mechanical Institute).