Stewart was West Ham's top scorer playing a vital part in their victory, including two goals in the fourth round against Leyton Orient and a last minute penalty winner in the quarter-final against Aston Villa.

In the semi-final replay on 16 April 1980, against Everton, Stewart was moved into central defence replacing an injured Alvin Martin.

[4] The following season Stewart was a vital member of the team which won the 1980–81 Football League Division Two, playing 41 games and scoring five goals, all penalties.

In 1989, with West Ham fighting a relegation battle, Stewart suffered a serious injury in the first half of a game in January against Derby County.

His last game came on 4 May 1991 in a 1–1 draw at Selhurst Park against Charlton Athletic[3] Following his run of injuries, aged 31, Stewart was not offered a further contract and was released on a free transfer.

[3] Despite playing in defence he was sent off only twice in his West Ham career, neither for fouls committed but on both occasions for comments made to referees or linesmen in games against Aston Villa and Liverpool.

Following his performances with newly promoted West Ham in the 1980–81 season, Stewart was called up by manager Jock Stein for Scotland making his debut on 15 May 1981 against Wales in Swansea.

[13] His last managerial post, with Forfar Athletic, came to an end in November 2004 when he was sacked after a 5–1 first round Scottish Cup defeat by Montrose.