[2] He made his debut for George Kay's "Reds" in the Football League four years later, against Manchester City at Anfield on 17 April 1948.

[2][6] He replaced Billy Morris as Jimmy McIlroy's midfield partner in the 1952–53 campaign, and scored 16 goals in 46 appearances as the "Clarets" posted a sixth-place finish under the stewardship of Frank Hill.

[6] Shannon claimed nine goals in 33 matches in the 1953–54 campaign, but after Alan Brown was installed as manager he only found the net just once in 43 appearances in 1954–55.

[6] Shannon retired from playing first-team football in August 1959,[2] and captained Burnley's reserve team for a year.

[5] In 1962, he joined Billy Wright's backroom staff at Arsenal, rising to the rank of assistant manager.

Bury finished bottom in his first season in charge, and Shannon was sacked, only to be re-instated two months later following boardroom changes at Gigg Lane.

After Bury's relegation, Shannon replaced Stan Mortensen as manager of Blackpool, with whom he had instant success, finishing as runners-up to Huddersfield Town and winning promotion back to the First Division.

This was achieved without the services of the club's star player, Tony Green, who sat out the entire 1969–70 season due to injury.

He was replaced, in a caretaker role, by Jimmy Meadows; his permanent successor at Bloomfield Road was Bob Stokoe.

He also led the club to victory in the Greek Cup in 1972 with a 2–1 win over Panathinaikos at the Karaiskakis Stadium; Giorgos Koudas scored both goals.

[citation needed] He moved on to another Salonica club, Iraklis Thessaloniki, with whom he won their first and only major trophy to date, the Greek Cup, in 1976, as they beat Olympiacos on penalties at the Nikos Goumas Stadium.

At his memorial service at the Square Methodist Church, Dunstable, former Manchester United manager Wilf McGuinness gave a speech.