Gollan was born in Paddington, London, the son of Spencer Gollan, a racehorse owner and keen sportsman from New Zealand. He started his sport career as a competitive swimmer, encouraged by his father.
In 1920 Gollan was runner up to Jack Beresford in the Diamond Challenge Sculls at Henley Royal Regatta[4] and in the Wingfield Sculls. From 1920 he was Beresford's toughest competitor in the Wingfield Sculls which in 1921 were decided on a foul after Beresford's boat was holed in a clash with Gollan. Both scullers were being steered by their fathers and so in 1922 it was decided that fathers of competitors should not act as pilots or steer the cutters. Gollan was again runner up to Beresford in that year. In 1923 Gollan won the London Cup at the Metropolitan Regatta but was runner up in the Diamonds to M K Morris, and to Beresford in the Wingfield Sculls. In 1925 he was again runner-up to Beresford at Henley.