In a career which lasted from 1840 until his death in 1898 he trained the winners of twenty-eight British Classic Races, a figure surpassed by only two other men.

[2] Dawson began training racehorses in Scotland in 1840, where his main patrons were Lord Kelburn and William Hope Johnstone.

[3] In 1846, Dawson moved to England to become the stud manager and private trainer for Lord John Scott at Yew Tree Cottage at Compton, Berkshire.

While working for Scott he recorded his first Royal Ascot win in 1851 and trained his first Classic winner when Catherine Hayes won The Oaks in 1853.

When Scott sold his horses to James Merry in 1857, Dawson continued to train them but moved his base to Russley Park, near Lambourn.

In 1866, Dawson moved to Newmarket, basing himself first at St Mary's Square and then Heath House, where he had his greatest successes.

[2] Now in his seventies, and often unable to walk because of chronic gout, Dawson won a further four Classics for Rosebery, including successive Derby winners in 1894 (Sir Visto) and 1895 (Ladas).