A centre half back, Deacon began his league career in 1942. He was a premiership player for Carlton in 1945 (after acting as captain-coach of an Army stores team that won all ten games in a services competition in Darwin) and 1947, the latter in a year which he won both a Brownlow Medal and shared Carlton's best and fairest medal with his captain Ern Henfry. The previous season Deacon had finished fourth in the Brownlow Medal count but this time around finished on top, thus becoming Carlton's inaugural winner of the award.
Deacon left Carlton after the 1951 season and became captain-coach for Preston in the Victorian Football Association (VFA), the club where he had played for prior to being recruited by Carlton. He later served as Carlton vice-president and club secretary.
He is the centre half back in Carlton's official 'Team of the Century'.
Off the field, Deacon worked for many years for long-serving VFL and Carlton president Sir Kenneth Luke. Bertram Deacon died of a heart attack on 3 January 1974 while on holiday at Balnarring. Deacon was just 51 years of age and died despite the desperate efforts of his Preston team-mate, Pat Foley to revive him.