Aldridge spent two seasons at Real Sociedad, becoming the first non-Basque player to sign for the club in several decades as they abandoned their selective recruitment policy.

A Liverpudlian by birth, he was recruited to play for the Republic of Ireland as part of Jack Charlton's "Granny Rule" policy: his great-grandmother was from Athlone, and travelled to Liverpool to settle in the 19th century.

He began his career in the mid-1970s at non-league South Liverpool, before getting his break in the professional game when, aged 20, he signed for Newport County in the Fourth Division on 2 May 1979 for £3,500.

[9] Alridge was sold to Oxford United on 21 March 1984,[10] when the club was preparing for their Third Division promotion run-in under the management of Jim Smith.

His 34 goals (30 in the league) in 1984–85 broke the club's goalscoring record for a single season,[11] as Oxford gained promotion to the old First Division for the first time.

He was the third-highest scorer in the division (only surpassed by Gary Lineker and Frank McAvennie) and netted six goals in United's League Cup-winning run in 1986 which culminated in a 3–0 victory over Queens Park Rangers in the final at Wembley.

He also scored one of the two Oxford goals that defeated Manchester United in Alex Ferguson's first game as manager, on 8 November 1986, maintaining his fine form into the 1986–87 season.

[12] In early 1987, Liverpool were losing striker Ian Rush to Juventus at the end of the 1986–87 season and needed a proven and experienced replacement.

Dalglish had been interested in signing other strikers, including Chelsea's David Speedie and Arsenal's Charlie Nicholas, for a number of months before settling on Aldridge.

[8] Liverpool ended the season trophyless, including a Wembley defeat to Arsenal in the League Cup final, for which Aldridge was ineligible.

[17] With Wimbledon 1–0 up in the FA Cup final at Wembley, midway through the second half, Liverpool were awarded a spot-kick when Aldridge himself was fouled, and he took the resulting penalty.

Aldridge had scored all eleven of his penalty kicks that season, but goalkeeper Dave Beasant noticed that he always placed the ball to the keeper's left.

1–0 down in injury time, Liverpool conceded another goal to Michael Thomas with virtually the last kick of the season, thus losing the League title.

This transfer made Aldridge the first non-Basque player to sign for Sociedad in several decades as they changed their selective recruitment policy.

[10][21][22] Aldridge scored 40 goals in 75 appearances for Sociedad over two seasons,[21] with the club encouraged to make more signings from English football in 1990, namely Dalian Atkinson and Kevin Richardson.

Insulting graffiti was written on the stadium, a fan spat on the ground when Aldridge passed in the street, and his family found it hard to adapt to the different lifestyle in the Basque country.

He made his debut for Rovers, aged 32, on 17 August 1991, scoring both the goals in a 2–0 victory over Brighton & Hove Albion at the Goldstone Ground.

[25] Aldridge's goals helped Tranmere reach their highest position ever in the league – top-six finishes in the second tier in 1993, 1994 and 1995 – which delivered playoff places each time, but all of them ended in semi-final defeats.

He also came close to winning another major trophy as Rovers took Aston Villa to a penalty shoot-out in the 1993–94 League Cup semi-finals before bowing out to the eventual competition winners.

During the 2000 League Cup final, Aldridge slapped the face of Leicester's Theo Zagorakis after he applauded the referee's decision to send off Clint Hill.

[29] Aldridge had already been recruited to play for the Republic of Ireland by the time he was approached by Liverpool at the start of 1987, qualifying through his grandmother, who was from Athlone.

That summer, Aldridge played for the Irish side which had qualified, under Charlton, for Euro 88 in West Germany, their first-ever major finals.

[33] Aldridge withdrew himself from Ireland's World Cup qualifying tie with Spain at Lansdowne Road on 26 April 1989, as he felt unable to participate in the game due to his grief over the Hillsborough disaster.

Trailing 2–0 to Mexico in a group game in Orlando, Florida, Charlton tried to send Aldridge on as a substitute but was delayed by a perceived sluggishness from the officials.

Manager and player both launched expletive-laden tirades which were clearly heard by television viewers, with Aldridge having to be restrained from attacking the fourth official and a FIFA representative.

Aldridge is now a pundit with various media organisations – most notably with Radio City 96.7 where he summarises on the station's Liverpool commentaries home and away.

Despite not having a natural singing voice, Aldridge won the competition and in the process raised money for his nominated charity Temple Street Children's Hospital.