Career
Coulson joined Peterborough United at the age of 13, having previously played for Rushden & Diamonds. He was drafted into first team action in April 2012, for Posh"s last home game of the season, a 2–2 draw with Watford. Coulson came on as a late substitute for Joe Newell, becoming Peterborough"s second youngest ever player behind Matthew Etherington.
On 30 April 2012, Coulson agreed a two and a half year professional contract, with an option of an extra year, which will be completed on his 17th birthday.
Coulson had his contract cancelled by mutual consent on 2 June 2014, and he became a free agent. On 1 November 2014, he made his debut for Deeping Rangers coming on as a substitute in the first round of the FA Vase against Wivenhoe Town.
Scoring his first goal for the club just 2 weeks later in a county cup match against Holbeach United.