Capleton began his career with Tottenham Hotspur in the early 1990s. Unable to break into the first team, however, he joined Southend United in 1992. Again at a seemingly dead-end, he joined Billy Ayre's Blackpool the following year on a free transfer. Due to his role as back-up to the Seasiders' first-choice goalkeeper Lee Martin, Capleton only made eleven league appearances in his three years at Bloomfield Road. He was released in May 1996.
After two years with Billericay Town, Leyton Orient offered Capleton a return to the professional game. After only a month with the Londoners, his first club, Southend, signed him for just one game in October 1998. He returned to the club on a permanent basis, however, in March the following year.
Capleton went on to make 56 appearances for Southend in two years. His third season at Roots Hall was spent on loan to Grays Athletic. He made the move permanent in 2002.
He signed for St Albans in the summer of 2004 but was released at the end of the season. He then joined his former club Billericay Town for a season.
In 2007 he joined Canvey Island as goalkeeping coach.
He currently works as a personal fitness trainer and coaches young children in the South West London area