McGrath was born in Greenford, Middlesex,[1] to a Nigerian father who met his Irish mother during his medical studies in Dublin.

She was strongly advised to give her son up for adoption at the Mother and Baby home in Acton, where she refused to do so numerous times.

McGrath made his debut for St Patrick's Athletic in a League of Ireland Cup clash with Shamrock Rovers on 30 August 1981 at Richmond Park.

He missed out on a place in the FA Cup victory over Brighton & Hove Albion the following year but soon ousted Gordon McQueen to become the regular partner to Kevin Moran in the centre of defence.

[14] A dismal start to the 1986–87 season saw Ron Atkinson sacked as manager and replaced by Alex Ferguson in November 1986, but McGrath initially remained a regular member of the first team.

[15] By the 1988–89 season, McGrath was struggling with knee injuries and was becoming a less regular member of the first team, facing competition from new signings Steve Bruce and Mal Donaghy.

Under Jozef Vengloš, the first top-flight manager to hail from the European mainland, McGrath became a consistent mainstay of the Villa lineup.

After Vengloš' solitary season (1990–91) at Villa, Ron Atkinson took over, building a decent squad in the early Premier League era.

[19] In 1990, the Republic of Ireland qualified for its first FIFA World Cup, in 1990 in Italy, eventually reaching the quarter-finals, where they lost to the hosts (1–0 in Rome), with McGrath ever present in the lineups (five matches, 480 minutes played).

[20] In the Republic of Ireland's opening game of the 1994 World Cup – a 1–0 win against favourites Italy, thanks to Ray Houghton's early goal – in a perfect example of his commitment to the game, McGrath put up an astonishing defensive performance despite excruciating shoulder problems, including blocking a shot from Roberto Baggio with his face.

[21] In an interview with FourFourTwo, he admitted to playing football while still under the influence of alcohol; additionally, his recurrent knee problems resulted in him undergoing a total of eight operations during his career.

McGrath's autobiography, Back from the Brink, co-written with journalist Vincent Hogan, was the inaugural winner of the William Hill Irish Sports Book of the Year (2006).

[27] Paul's half-sister Okune McGrath died in March 1994 due to complications stemming from a lifelong rare blood disorder.

[5] McGrath would return to play for Aston Villa on 5 November 1989, in a 6–2 victory over Everton, but during the game had to hide wounds to his wrists using wristbands.