Northampton born outside right Bobby King began his senior football career with Northampton Town, having signed for them in October 1937 he made his debut for The Cobblers in an FA Cup tie against Cardiff City the following month, playing twice more in his debut season, his Football League debut coming two weeks later at Notts County. Having come into the side at the start of the new season, he missed only two games in 1938-39, scoring 6 goals, and in November 1939, two months after the outbreak of the Second World War had forced the suspension of peacetime football, he signed for First Division Wolverhampton Wanderers after 48 appearances for The Cobblers.
King had to wait until the War was over before making his debut for Wolves in peacetime football, which came in an FA Cup tie against non league Lovell’s Athletic in January 1946, King scoring in the return, an 8-1 victory at Molineux. In Wolves’ first peacetime season he played 9 matches as Wolves finished third in the League Championship, but returned to Northampton Town in December 1947 after 4 goals in 13 games in old gold and black. He played three further seasons for The Cobblers, scoring 17 goals in 56 appearances including a hat-trick in a 4-2 win over Ipswich Town in April 1948, before joining non league Rushden Town in the 1950 close season, where he played until his eventual retirement.