Born in Solihull, as a player Deehan was a striker who is best known for productive spells with Aston Villa and Norwich City. With Villa he was a member of the team that won the 1977 Football League Cup Final against Everton and was a member of the Norwich sides which won the 1985 Football League Cup Final and the Second Division championship in 1986. On 24 January 2012 he was appointed as Director of Football at League Two club Plymouth Argyle. Argyle stood at 22nd in League Two at the time of his appointment.