[1] Kiernan was a Fitzroy local and played for the Maroons in the inaugural VFL season, topping their goalkicking in their first two years, and again in 1900.

Additionally, Kiernan was selected in Fitzroy's 1899 Grand Final side but failed to arrive at the ground on time and missed out on playing in a second premiership.

He fell out with the Fitzroy committee and in 1904 attempted to cross to Collingwood but his request was blocked by VFL delegates.

Kiernan instead joined Victorian Football Association (VFA) club Brighton, but made a brief comeback at Fitzroy in 1911.

With his football career over, Kiernan turned his attention to cricket and from 1910 to 1919 played 10 first-class matches for Victoria, three of them in the Sheffield Shield.