McCreadie started his footballing career with amateur Scottish side Drumchapel before moving to Clydebank Juniors and then East Stirlingshire.

A talented and pacy attacking full-back with impressive timing, McCreadie was a regular starter in the Chelsea sides of the 1960s and 1970s alongside the likes of Bobby Tambling, Peter Osgood and Charlie Cooke.

While he only scored five goals for the club throughout his career, McCreadie scored a memorable winner in the League Cup final of 1965 in which he dribbled 80 yards up the pitch before slotting the ball past Leicester City goalkeeper Gordon Banks to give his side a 3–2 first leg lead, which ultimately won the trophy for his club as the second leg at Filbert Street ended in a 0–0 draw.

Nevertheless, McCreadie re-built the side – taking the captaincy from John Hollins and giving it to 18-year-old Ray Wilkins in the process – and with no money to spend, put together a team of youth players and veterans from the club's heyday.

McCreadie left for the North American Soccer League in the late 1970s and was appointed manager of the Memphis Rogues, with whom he played one game in 1979,[5] and later the indoor Cleveland Force before finally retiring from football in 1985.