He was bred by John Bowes of Streatlam Castle, who also bred the Derby winners Mundig (ch c 1832), Cotherstone (b c 1840), and West Australian (b c 1850). His dam, Forget-Me-Not (b f 1843), bred as well by John Bowes, produced fourteen foals, of whom six were good winners.

Daniel O'Rourke was described by "The Druid" as the "lengthiest and most compact of the Birdcatcher family" as he was only 14.3 hands as a three year old and later grew to nearly 15.2 hands. He probably inherited his trademark tail from his grandsire, Sir Hercules (bl c 1826), who was noted for passing on tails with silver hairs at the root.

Later purchased by Sir Tatton Sykes, he retired to the Sledmere stud, where he was a great favourite. His offspring were said to be of a darker chestnut than most of the Birdcatchers and all of them had backs and legs of iron. The Druid noted that Daniel's fillies had always a great deal more grey at the root of their tails than did the colts, and that this trait used to be called "Match'em Arms". Daniel was eventually sold to the Austrian government for 800 guineas.