Hailing from Standish near Wigan, a former Hindley amateur, Deacon made his senior professional début four days before his 18th birthday as a substitute for Oldham in a 48–6 RL Challenge Cup fourth round home victory over Rochdale Hornets on 9 February 1997.

Deacon scored a try and goal on his début for the Bradford Bulls at scrum-half in a 36–10 Super League home victory over Huddersfield Giants on 28 June 1998.

Deacon played for the Bradford Bulls from the interchange bench in their 2001 Super League Grand Final victory against the Wigan Warriors.

As Super League VI champions, the Bradford Bulls played against 2001 NRL Premiers, the Newcastle Knights in the 2002 World Club Challenge.

Deacon played for the Bradford Bulls at scrum-half, kicking three goals in their 2002 Super League Grand Final loss against St. Helens.

[5] On 23 June 2006, Paul Deacon broke the record points scored for a Bradford Northern/Bradford Bulls player (1,834), which was previously held by Keith Mumby.

As well as a testimonial match against his hometown club Wigan Warriors in January, Paul Deacon's name also appeared on all away jerseys to commemorate his loyalty to the Bradford Bulls.

In July 2015 it was confirmed that Deacon would switch codes and join Premiership rugby union side Sale Sharks as attack/skills coach.