Born in Bolton, Lancashire, Ainscow began his career with Blackpool as an apprentice, making his debut when then-Seasiders manager, Bob Stokoe, picked him to play in the 1971 Anglo-Italian Cup.
Ainscow played in the competition's final, on 12 June 1971 against Bologna at the Stadio Renato Dall'Ara, which Blackpool won 2–1 after extra time.
[2] Still without a league appearance, Ainscow played the whole game before being substituted prior to the end of extra time due to exhaustion.
Also that same season he scored his only hat-trick, when Blackpool beat local rivals Preston North End 3–0 at Deepdale on 19 December 1972.
He returned to England in 1984 to play for Wolverhampton Wanderers, before moving to Blackburn Rovers in 1986, where the following year he was part of the team that won the Full Members Cup after a 1–0 victory over Charlton Athletic at Wembley.