Howells made his debut for Tottenham Hotspur as an 18-year-old in 1986, scoring in a 2–1 win against Sheffield Wednesday. He spent 12 more seasons at White Hart Lane, made 335 first-team appearances, and was on the winning side in the 1991 FA Cup Final. Howells also represented Southampton, scoring once against Arsenal, and Bristol City before retiring from the game in 2000 due to a persistent knee problem.