Hailing from the Victorian Football Association (VFA) club Coburg, Fanning was a strongly built forward standing at 193 cm and weighing 102 kg.

[2] Fanning made his senior debut in 1940 and played in that year's Grand Final victory over Richmond.

He topped the VFL's goalkicking charts in 1943 (62 goals), 1944 (87) and 1945 (67),[3] a year in which he also won Melbourne's best and fairest award.

In Round 19, 1947, he kicked 18 goals, 1 behind, in a game against St Kilda, which remains the record for most goals in a VFL/AFL match to this day;[4][5] this was coincidentally Fanning's final appearance in a VFL match.

Fanning held the Western District record for most goals in a game by kicking 22 against Heywood in 1949.