Northmore began his career as a trainee with
Torquay United, having previously been on the books of
Plymouth Argyle and
Swindon Town. He turned professional in August 1998, making his first team debut away to
Gillingham in the
Auto-Windscreens Trophy on 7 December 1999. His league debut came on 5 February 2000 in Torquay's 4–0 win at home to
Halifax Town after regular keeper,
Neville Southall had been injured in the previous league game. Northmore was highly rated by Southall as his understudy, but, when Southall was released at the end of the season,
Stuart Jones was signed and took over as first choice keeper. Northmore replaced Jones early in the season and was a regular for the remainder of the season as Torquay struggled to avoid relegation to the
Conference. However, Northmore was dropped for the crucial final game of the season, away to
Barnet, a game that saw Jones save a penalty and Torquay survive at Barnet's expense. When
Roy McFarland took over as Torquay manager, one of his first signings was
Kevin Dearden, whose consistent form kept Ryan on the substitutes bench for most of the season.
Leroy Rosenior took over as Torquay manager at the end of the season and Northmore was relegated to third choice keeper after the signing of
Jamie Attwell. After his release by the
Plainmoor side in October 2002, he became a full-time student at the
University of Bath and played for the university side
Team Bath in the
Western League. He moved to
Conference side
Woking in June 2003, but was unable to dislodge another former Torquay keeper
Ashley Bayes from the goalkeepers position and was allowed to join
Bath City on loan in December 2003 and
Yeovil Town on loan in March 2004. Northmore returned to Team Bath on a free transfer in the 2004 close season, but joined
Weston-super-Mare on loan in September 2004. However, Northmore was recalled by Team Bath in December. Later that month Northmore returned to Weston on loan until the end of the season, when he was signed on a permanent basis by Weston. Northmore signed a new contract with Weston in June 2007. Following his exit from Weston in July 2009, Northmore signed for Dorchester before retiring from playing in 2010. ==Coaching and managerial career==