St John, born in Motherwell in 1938, also enjoyed a successful punditry career after hanging up his boots, striking up a TV partnership with ex-England forward Jimmy Greaves to helm the popular Saint and Greavsie on ITV.
A two-time title winner with Liverpool, St John scored 118 goals for the Reds in 425 appearances over ten years.
His most important goal came in 1965, and ‘was responsible for the single greatest moment of the [Bill] Shankly era’, according to Liverpool themselves.
St John netted a header in extra-time at Wembley to secure a 2-1 win over Leeds which claimed Liverpool their first ever FA Cup.
He won First Division titles in 1963/64 and 1965/66, as well as the Second Division in 1961/62 and three Charity Shields.
Liverpool said they were ‘deeply saddened’ by the news of a ‘Reds legend’.
A statement released by the club on the behalf of St John’s family read: “It is with a heavy heart that we have to inform you that after a long illness we have lost a husband, father and grandfather.
“He passed away peacefully with his family at his bedside.
“We would like to thank all the staff at Arrowe Park Hospital for their hard work and dedication during these very difficult times.
“The family would be grateful for privacy at this extremely sad time.”
As well as his lengthy spell with Liverpool, St John also represented hometown club Motherwell, South African sides Hellenic and Cape Town City, as well as Coventry and Tranmere Rovers.
On the international stage St John made 21 appearances for Scotland, scoring nine goals, and he was inducted into the Scottish Football Hall of Fame in 2008.
He hung up his boots in 1973 and became Motherwell manager for a single season, moving onto Portsmouth for three years.
After short spells as assistant manager at Sheffield Wednesday and Coventry, St John moved into punditry and struck up a hugely successful TV partnership with Greaves.
Saint and Greavsie ran from 1985 to 1992 and was popular with viewers, and included interviews with non-football legends including Mike Tyson and Chris Eubank.
The pair’s popularity was demonstrated by the fact they were both made in Spitting Image puppets.
Once Saint and Greasvie came to an end, St John remained working as a co-commentator and pundit.