[5] His signing, even as a 12-year-old schoolboy who had yet to play a competitive senior match proved problematic; Spencer was Catholic and the club had a strong Protestant culture.

[6] His decision to sign for Rangers meant that he was regularly threatened and challenged to fights at the Catholic school he attended, while Celtic-supporting members of his family would walk by him in the street, and have never spoken to him since.

Spencer remained a fringe player at Rangers and after a further loan spell with Lai Sun[8] of Hong Kong was sold in 1992 to Chelsea for a fee of £450,000, having made 20 appearances in all competitions over five years.

[10] In November 1996, with Gianluca Vialli and Gianfranco Zola now on Chelsea's books, their manager Ruud Gullit sold Spencer for £2.5 million to another West London club, Queens Park Rangers, then in the second tier of English football, the First Division.

Reunited with Walter Smith, his former manager at Rangers, Spencer's career at Everton quickly stalled, as he struggled to regain the performance levels required as a Premiership player.

On 30 August 2009, Spencer was inducted into the Rapids Gallery of Honor at halftime of the Dynamo's 1–0 loss to the Rapids Having played three matches for the under-21s while at Rangers,[13] Spencer's prominence at Chelsea saw him gain the first of 14 caps for the Scotland national team in November 1994, appearing as a substitute in a 1–1 draw with Russia at Hampden Park in Scotland's successful campaign to qualify for the 1996 European Championship.

He played in all three matches at the finals, starting in the defeat to England and coming off the bench in the draw against the Netherlands and the win over Switzerland.

As his club career fluctuated he also featured less on the international scene, making one appearance at the outset of the 1998 FIFA World Cup qualification campaign, and claiming his last cap in a friendly against Wales in May 1997.

[14] Upon retiring from his playing career, Spencer joined Houston Dynamo as an assistant coach on Dominic Kinnear's staff.

[20] Known as a "players coach", Spencer installed an attacking style of play and a blue-collar, hard-working mentality to the Timbers in his first season at the helm.