The Second World War halted Gibbons' career between 1939 and 1945. In 1945, Gibbons turned professional and signed with Bradford Park Avenue to play the 1945/46 season in an expanded FA Cup. The Avenue advanced to the sixth round, with Gibbons scoring four goals in an 8–2 fourth round second leg rout of Manchester City on 30 January 1946. Avenue were admitted to the Second Division for the 1946/47 season, with Gibbons making 42 appearances and scoring 21 goals. In August 1947 he returned to Brentford, newly relegated to the Second Division, for a club record £8000 fee. Gibbons was the club's top scorer during the 1947/48 season, scoring 13 times. He made 56 appearances and scored 16 goals before retiring in February 1949.
Gibbons became manager of Second Division side Brentford in February 1949, taking over from Harry Curtis, the most successful manager in the club's history. Gibbons had been groomed to succeed Curtis at the helm. In the summer of 1949, Gibbons brought former Bradford Park Avenue teammate and future England manager Ron Greenwood to the club he supported as a boy, naming him captain. In February 1951, Gibbons brought football analyst Charles Reep to Griffin Park on a part-time basis until the end of the 1950/51 season. Reep helped improve the team's goals-to-games ratio, which saved them from relegation. Gibbons managed Brentford until the end of the 1951/52 season, making three consecutive top ten finishes in the Second Division, but he found himself at odds with the club's board during a difficult time financially for the Bees. A falling out with Jimmy Hill and Ron Greenwood towards the end of 1951 saw the Bees' form tail off, with the club finishing the 1951/52 season in 10th place, having been as high as 2nd mid-season. Gibbons resigned in August 1952 and was replaced by his assistant, Jimmy Bain.