Darius was a "good-looking"[1] bay horse with one white foot, standing 16 hands high, bred by his owner Sir Percy Loraine.
On his three-year-old debut, Darius was beaten by Tudor Honey in the 2000 Guineas Trial Stakes at Kempton Park Racecourse in April.
Darius reverted to one mile at Royal Ascot and won the St James's Palace Stakes as the even money favourite, beating Umberto by a short head[7] with Narrator in third.
Two weeks later he raced against older horses for the first time in the Eclipse Stakes over ten furlongs at Sandown Park where he carried seven pounds more than weight-for-age[7] and finished second to the four-year-old King of the Tudors.
[13] He was then moved back up in distance for the King George VI and Queen Elizabeth Stakes but finished unplaced behind the French-trained colt Vimy.
[15] On his final appearance, Darius was one of two British runners sent to the United States to contest the fourth running of the Washington, D.C. International Stakes at Laurel Park Racecourse.
[17] In their book A Century of Champions, based on a modified version of the Timeform system, John Randall and Tony Morris rated Darius an "average" winner of the 2000 Guineas.
The best of his progeny included Pia (Epsom Oaks), Pola Bella (Poule d'Essai des Pouliches, Prix du Moulin), Derring-Do, Dart Board (Dewhurst Stakes) and Varano (Derby Italiano).