Spencer Prior was a £300,000 signing from Southend in June 1993. Primarily a centre-back, Spencer had played 135 league games for the Shrimpers before his move to Carrow Road. At the time he was also a target for Wolves and when interviewed about his decision to join Norwich, he quoted that he preferred to take his chance of playing in the UEFA cup rather than the First Division. 89 appearances were clocked up for the Canaries before he joined Leicester City for £600,000 in the summer of 1996. He was a regular in the Leicester defence (34 league appearances) throughout their successful 1996/97 season that has seen them win the Coca Cola Cup and reach the fifth round of the FA Cup. He made another 30 appearances in 1997/98.

Spencer was then signed by Derby County in August 1998 for £700,000 to replace Christian Dailly who joined Blackburn following Colin Hendry's move to Rangers.

According to the News of the World (28th November 1999), Spencer has been told by Rams manager Jim Smith that he can leave the club. Ipswich and Hearts were rumoured to be interested but whilst Hearts prefer a player swap, Smith wants about £600,000 in order to sign French defender Jean Francois Hernandez from Spanish club Rayo Vallecano. A fortnight later saw the Sunday tabloids link Spencer with a move to Steve Bruce's Huddersfield.

BBC's Ceefax reported on 26th January 2000 that Nottingham Forest had made a £300,000 bid for Spencer. This move fell through scuppering Derby's plans to sign Stig Inge Bjornebye from Liverpool. In early February 2000, the media reported that Sheffield Wednesday were preparing a move for Spencer to bolster their defence in their struggle against relegation from the Premiership.

Spencer signed for Manchester City on 22nd March 2000 for a fee rumoured to be either £300,000 or £500,000 and was instrumental in assisting City to promotion to the Premiership. By February 2001, Spencer was linked with moves to First Division Wolves and Crystal Palace, the latter having allegedly offered £700,000 for a player on the fringes of Man City's first team. On March 18th 2001, the Sunday People claimed that David Platt was hoping to bring Spencer back to the Midlands for £700,000 to strengthen Nottingham Forest's bid for promotion via the play-offs. However Spencer's £500,000 a year wages proved to be a problem for Forest.

Placed on the transfer list at City following their relegation in May 2001, Forest again were linked with a move for Prior but surprisingly Teamtalk linked him with a move to Wales to join ambitious Cardiff City. However his wages were again likely to prove problematic. The move was finally agreed with both partners happy although Spencer should've checked the small print inserted by Bluebirds chairman Sam Hamman that stated Spencer had to "have intimate relations with a sheep" and eat "sheep's testicles" !

In May 2002, Spencer was linked with a move to Wigan to replace Arjan De Zeeuw who was likely to join Birmingham. Cardiff's financial problems as a result of the ITV Digitial fiasco meant that they would hope to cut costs and Spencer as a high wage earner would be a prime target. In the end, Spencer stayed with the Bluebirds for another two seasons before he was released in May 2004.

In June 2004, Peterborough manager Barry Fry revealed that Spencer was one of three players that he was talking to in the prospect of bringing them to London Road. At the beginning of July 2004, Spencer returned to Essex joining Colchester United on trial. When that fell through, he joined his old club Southend on trial. The Shrimpers managed to find the finances to bring Spencer back to his first club on a permanent basis. He was in the Southend team that won the League Two play-off finals at the Millennium Stadium against Lincoln City on 28th May 2005.

Spencer retired at the end of the 2006/7 season and is reported to have moved to Australia where he is commentating on football for Fox Sports. At the end of December 2008, it was reported that he had signed for Newcastle Jets of the Australian A-League as a guest player just days after the Jets lost captain Jade North to South Korean side Incheon United

He currently combines being the Assistant Coach for the Women's National Side, appointed in January 2011, with running his own football distribution company Love Football. He was appointed Technical Director for Football Federation Tasmania in August 2013, working on player development and coach education.

In 2016, he signed a two year contract to manage the Thailand women's national team.

In July 2019, he joined Thai League 1 club Port F.C. as Technical Director. They won the 2019 Thai FA Cup.

He returned to Australia in September 2020 joining APIA Leichhardt's Women's Team as Head Coach.

By November 2022 he was also head coach of the Papua New Guinea women's national side. He took the job after being approached by the Oceania Football Confederation (OFC) and admits it is tougher than anything he has faced in football before.

"I worked in Thailand for two years, that was challenging but this is on another level," he told BBC Sport. "When I first started, we arrived in Canberra for a training camp, we had 19 players but no staff, no physio or doctor, no health insurance. These are basic things these players should have.We are trying to put in place things to make them prepared, to do in four months what others do in four years."