[6] In the Claret Stakes at Newmarket on 9 April Sir Harry was opposed by some of the previous year's best three-year-olds including the colts Admiral Nelson (the 6/4 favourite), Telegraph and Schedoni as well as the filly Bellissima, winner of The Oaks.

On 14 April he was beaten in a 500 guinea match race over ten furlongs against Mr Baldock's horse Schedoni, to whom he was conceding half a pound.

On this occasion, Sir Harry carried half a pound less than his opponent and reversed the York form to win a prize of 200 guineas.

[12] A third match against Symmetry, with Sir Harry conceding six pounds, had been scheduled for the next Newmarket meeting, but Mr Cookson withdrew his horse and paid a forfeit.

On 26 August he carried top weight in the York Oatlands Stakes over two miles and finished last of the three runners behind Sir Harry Tempest-Vane's St Leger winner Cockfighter.

[15] On the following afternoon Sir Harry started 6/4 favourite for the Great Subscription Plate and finished last of the five runners over four miles.

On 9 April he conceded at least ten pounds to his opponents in a race over the Duke's Course at Newmarket and won from Jack Andrews, Hippona and Telegraph.

[18] On his next start three days later, Sir Harry ran in the colours of Mr Bullock in a ten furlong Subscription Plate.

[23] Two weeks later, Sir Harry made his first appearance for his new owner in a King's Plate at Lewes where his opponents were Warter and Slapbang.

With Slapbang being withdrawn, the two winners then took part in deciding heat, which Sir Harry won to claim the prize, having galloped twelve miles in the course of the afternoon.

Racing over one mile at level weights, Sir Harry started a slight favourite but was narrowly beaten by Lord Sackville's horse.

[25] The winning margin was so small that Concannon tried to claim a victory for Sir Harry before the official result was announced, creating "great confusion" among the racegoers.

Sir Harry began his breeding career at Dennis O'Kelly's stud at Cannons, near Little Stanmore, Middlesex, where he stood at a fee of five guineas alongside the established stallions Dungannon and Volunteer.