The highlight of his career so far is a collection of five top-level wins, the kind of races that carry real prestige and attract the best horses in the country. He has won at Cheltenham and Ascot — two venues where reputations are made — as well as Huntingdon, where he struck again as recently as 5 February 2026, followed by another top-level win at Wincanton just nine days later. Back-to-back wins at that level in the space of a fortnight is not something that happens by accident. It points to a jockey in form, riding with confidence and trusted by trainers with their best horses.
His most productive relationship in the saddle is with trainer Harry Derham. Across 187 rides together, they have combined for 40 wins — a win rate of just over 21%, meaning they win roughly 1 in every 5 races as a partnership. In a sport where chemistry between jockey and trainer matters enormously, that kind of consistency over such a large number of rides is a genuine sign of trust on both sides. O'Brien also has a promising partnership developing with a horse called Norn Iron, winning 2 of the 5 races they have tackled together.
There are specific conditions and tracks where O'Brien looks especially dangerous. At Haydock Park, he has won 3 races from just 6 rides — half the time he turns up there, he leaves with a winner. On fast, dry ground he has converted 1 from 3, a small sample but one that hints at a rider who handles the quicker conditions well. At 182 career winners and still only four years in, the trajectory here is unmistakably upward.
| Course | Races | Wins | Win rate |
|---|---|---|---|
| Chepstow | 24 | 4 | 16.7% |
| Newbury | 20 | 2 | 10% |
| Kempton Park | 17 | 4 | 23.5% |
| Huntingdon | 17 | 3 | 17.6% |
| Warwick | 13 | 2 | 15.4% |
| Exeter | 13 | 1 | 7.7% |
| Cheltenham | 12 | 1 | 8.3% |
| Wincanton | 11 | 2 | 18.2% |
| Fontwell Park | 11 | 1 | 9.1% |
| Musselburgh | 9 | 3 | 33.3% |
| Southwell | 9 | 1 | 11.1% |
| Bangor-on-Dee | 8 | 1 | 12.5% |
| Doncaster | 8 | 0 | 0% |
| Stratford-on-Avon | 7 | 3 | 42.9% |
| Uttoxeter | 7 | 1 | 14.3% |
| Taunton | 7 | 1 | 14.3% |
| Plumpton | 7 | 1 | 14.3% |
| Sandown Park | 7 | 1 | 14.3% |
| Leicester | 7 | 0 | 0% |
| Haydock Park | 6 | 3 | 50% |
| Newton Abbot | 6 | 1 | 16.7% |
| Ludlow | 6 | 1 | 16.7% |
| Ascot | 6 | 1 | 16.7% |
| Market Rasen | 6 | 0 | 0% |
| hereford | 5 | 1 | 20% |
| Carlisle | 5 | 1 | 20% |
| Worcester | 4 | 3 | 75% |
| Fakenham | 4 | 1 | 25% |
| Wetherby | 4 | 0 | 0% |
| Lingfield Park | 3 | 1 | 33.3% |
| Ffos Las | 3 | 1 | 33.3% |
| Kelso | 3 | 0 | 0% |
| Newcastle | 2 | 1 | 50% |
| Hexham | 2 | 1 | 50% |
| Aintree | 2 | 0 | 0% |
| Perth | 2 | 0 | 0% |
| Punchestown | 2 | 0 | 0% |
| Ayr | 2 | 0 | 0% |
| Catterick Bridge | 1 | 1 | 100% |
| Fairyhouse | 1 | 0 | 0% |
| Epsom Downs | 1 | 0 | 0% |