1920: two-year-old season Craig an Eran ran twice as a juvenile, beginning his track career by finishing second in the
Salisbury Racecourse Foal Plate in spring. At
Royal Ascot in June he finished unplaced behind Alan Breck in the
New Stakes.
1921: three-year-old season On 29 April Craig an Eran (ridden by Jack Brennan) started at odds of
100/6 (approximately 16/1) in the 113th running of the
2000 Guineas over the Rowley Mile at
Newmarket Racecourse.
Humorist started favourite while the best fancied of the other 24 runners included Monarch (
Middle Park Stakes), Alan Beck,
Polemarch and
Lemonora. Inside the final furlong Humorist held the lead but the complexion of the race changed in the final strides as Craig an Eran and Lemonora overtook the leaders. Craig an Eran crossed the line three quarters of a
length ahead of Lemonora with Humorist the same distance away in third. On 1 June Craig an Eran started 5/1 second favourite behind Leighton in a 23-runner field for the Epsom Derby. He produced a sustained run in the straight but was beaten a neck by Humorist after a "battle royal" with three lengths back to Lemonora in third.
Frank Bullock, who had ridden the colt in 1920, took over from Brennan when Craig an Eran was dropped in distance for the St James's Palace Stakes over one mile at
Royal Ascot and won at odds of 1/8. The form of the
British Classic Races was franked in late June when Lemonora won the
Grand Prix de Paris, the most valuable race in the world at that time. One day later however, it was announced that Humorist had died in his stable. On 15 July Craig an Eran was matched against older horses in the Eclipse Stakes over ten furlongs at
Sandown Stakes and, with Bullock in the saddle, won at odds of 2/7 favourite. He was followed home by Braishfield (
Sussex Stakes) and Pompadour (third in the
1000 Guineas), giving Alec Taylor a 1-2-3 in the race. On 7 September Craig an Eran started 1/4 favourite for the St Leger over furlongs at
Doncaster Racecourse and was reportedly regarded as a "certainty". He moved up to dispute the lead in the straight but failed to stay and finished fourth behind Polemarch, Franklin and Westward Ho!. Excuses were offered for the colt's defeat: it was reported that Taylor had been unable to train the horse to peak fitness on the prevailing
hard ground and that Craig an Eran had been bumped by Westward Ho! in the straight. The latter claim was refuted by the jockeys involved in an enquiry by the racecourse stewards. ==Assessment and honours==