During his career, Jennings played for Newry Town, Watford and in the top division with Tottenham Hotspur and Arsenal, winning the FA Cup with both of the north London rivals.

In total, Jennings made over 1,000 top level appearances, and despite being a goalkeeper, he scored from play in the 1967 FA Charity Shield.

[7] He also scored once, in the 1967 Charity Shield, from his own area, kicking the ball from his hands and sending a large punt down the field that bounced over Manchester United goalkeeper Alex Stepney and into the net.

[12] On 26 February 1983, he became the first player in English football to make 1,000 senior appearances, celebrating this milestone with a clean sheet in a goalless league draw for Arsenal at West Bromwich Albion.

[13] Jennings played his last game in the league for Arsenal against Sheffield Wednesday 25 November 1984 [14][15][citation needed], and he was finally replaced by John Lukic as the first choice keeper.

[16][17] After his retirement, Jennings returned to Tottenham Hotspur, playing mostly in their reserve side to maintain his match sharpness for Northern Ireland's 1986 World Cup campaign.

He was also briefly on Everton's books, having been signed as goalkeeping cover for the 1986 FA Cup Final against Liverpool, Neville Southall having been injured playing for Wales.

He is still associated with Spurs and hosts Corporate Hospitality fans in the Pat Jennings Lounges at White Hart Lane[18] and Windsor Park, Belfast.