Warmath began his tennis career on the municipal courts of Greensboro, where his family moved from his native Louisville. He honed his game at Darlington School in Rome, Georgia and went on to play at Duke for three years. Warmath won the Greensboro city championship twice. He made his mark in state tennis by winning the state junior title and seven doubles titles with three partners, including three times with Allen Morris, another Guilford County Sports Hall of Fame member. He served as president of the Greensboro Tennis Association and ran the state tournament for many years when it was played in Greensboro. Warmath was named to the North Carolina Tennis Hall of Fame in 1984.