Standing at just 170 centimetres tall and weighing 62 kg, Chicken (so nicknamed because his mother could never catch him when he was young) was a deceptively quick winger who played 150 games (kicking 31 goals) for Fitzroy between 1930 and 1940.

His early football was played as a rover, but a best-on-ground performance on a wing in his debut with Fitzroy had him permanently shifted to that position.

He received a knock behind the knee in the last five minutes of the match; and the injury was so severe that it ended his career.

In 1942 Smallhorn was the main organiser of a football competition in Changi which consisted of six teams named after VFL clubs.

Engaged to Violet Phyllis Burn in May 1939, and married in 1940, he was in the army when their son, Robert Leonard Smallhorn, was born.