Airdrie, Lanarkshire born inside right Peter McKennan began his football career with Whitburn Juniors before joining Scottish League Partick Thistle in 1934. His career was severely interrupted by the Second World War during which, having left Partick Thistle, he played in Ireland for Linfield in 1939 and Glentoran in 1940. In 1946 he returned to Partick Thistle from where he signed for Second Division West Bromwich Albion for £10,000 in October 1947, making his Football League debut at Bury on 1st November. However he only made 12 appearances, scoring 4 goals, before he was sold to Leicester City in March 1948.
He scored 7 goals in 18 appearances for The Foxes before joining Brentford in September 1948, for whom he scored 5 goals in an 8-2 victory over Bury in February 1949. As of January 2015, McKennan is the third of only three Brentford players to register five goals in a single League match. In total he scored 10 goals in 28 appearances for The Bees in 1948-49 but again moved on, this time joining First Division Middlesbrough in May 1949. This proved his only spell in the top flight during his career, and he top scored for the club with 16 goals in 1949-50 before joining Oldham Athletic in July 1951 having scored 19 goals in 43 appearances for ‘Boro. He then spent 3 seasons at Boundary Park, scoring 33 goals in 83 appearances for The Latics including 19 in his first season and 12 more in 1952-53 as Oldham won the Third Division (North) Championship. He finally had a brief spell as player-manager of Coleraine in Northern Ireland scoring 29 goals in 62 appearances for them before retiring from football in 1956.