He spent 12 years of his career playing for Slavia Sofia and is the club's all-time top goalscorer in the A Group with 136 goals.

Zhelyazkov is also the most capped player in the history of the club with 338 league appearances.

Zhelyazkov played in his home country for Minyor Radnevo and Slavia Sofia, in the Netherlands for Feyenoord, in France with RC Strasbourg, in Belgium for Beerschot, and for the Bulgaria national football team.

During 1983–84 season he formed a successful partnership with Johan Cruijff and Ruud Gullit, which led Feyenoord to the first league title since 1974.

This biographical article related to association football in Bulgaria, about a forward, is a stub.