Born into a legendary racing family, Jonjo O’Neill Jr grew up at Jackdaws Castle and was immersed in racing from an early age, with his father, Jonjo O’Neill, a Grand National winner, Gold Cup winner and two-time Champion Jump Jockey, before winning the Grand National and Gold Cup again as a trainer. His brother AJ O’Neill joined the training licence with their father in May 2024.   

However, it is his own ability that has established him as one of the leading jump jockeys of his generation. He rode his first winner under Rules in 2015 and quickly developed a reputation as a cool and accomplished rider over obstacles.  

His breakthrough came in the 2019/20 season when he was crowned Champion Conditional Jockey, a title that confirmed his growing status in the weighing room. Since then, O’Neill Jr has continued to build an impressive record, combining high-profile success for a range of trainers with his important role as retained rider for his father’s Jackdaws Castle yard.  

Since then, Jonjo has gone on to win multiple races at the Cheltenham Festival, most notably the Triumph Hurdle on Poniros for Willie Mullins. Jonjo has also formed a strong partnership with the Oliver Greenall & Josh Guerriero yard, who have provided him with rides on stable stars Jagwar and Iroko, the latter of which he rode to second place at the Grand National in 2026.