Doctor Syntax was a bay or brown horse standing 15 hands high, bred by William Knapton at Huntington in Yorkshire and owned during his racing career by Ralph Riddell of Felton Park in Northumberland.

[3] Doctor Syntax was named after a character created by the British writer William Combe in a series of satirical poems.

In July, Doctor Syntax crossed the Pennines to compete at Preston Racecourse and recorded his first win in a maiden plate.

At Morpeth on 17 September he won the first two races on the card, the Members' Plate and a Sweepstakes, starting favourite on both occasions.

As a five-year-old, Doctor Syntax won twice at Catterick in April but finished third to Mr Beal's filly Flot at Middleham.

[12] At Richmond in October, Doctor Syntax finished second to The Duchess in the Gold Cup and walked over in a Sweepstakes the following day.

[15] In 1820 the "celebrated"[16] Doctor Syntax was the subject of a painting by the artist James Ward R A, which is currently displayed at Brodsworth Hall near Doncaster.

On 5 July he won his fifth Lancaster Gold Cup, beating Sir Walter and the 1819 St Leger winner Antonio.

[20] Doctor Syntax began his final season by winning the Gosforth Stakes at Newcastle Racecourse in July and then won the Gold Cup at Pontefract in September.

[21] He escaped without serious injury, although the incident reportedly created great anxiety among the racing public who were concerned about the welfare of "the good old Doctor".

His undistinguished pedigree and unprepossessing appearance meant that he was not popular with breeders and attracted few top class mares.