[1] Embarking on a training program with former VFL boundary umpire Arthur Cook, Deller's fitness and endurance improved significantly.
Deller made his VFL senior grade debut in round 17 of the 1967 VFL season in a match between Essendon and Footscray at Windy Hill, a match in which the police attempted to arrest the Essendon runner, whom they mistook for a pitch invader from the crowd.
He returned to action midway through the 1975 VFL season,[1] and in 1976 was appointed along with Kevin Smith to co-umpire the Grand Final.
Immediately after retirement, Deller replaced Harry Beitzel as the part-time VFL Director of Umpiring.
During his time in charge, Deller oversaw a series of major changes including: In recognition of his on-field and off-field achievements, Deller has received numerous awards, including life membership of the AFL Umpires Association in 1975 and the AFL in 1993.