Born on April 22, 1982, in Ealing, West London, Paul Mulrennan graduated from the British Racing School in Newmarket before joining Brian Meehan in Lambourn, Berkshire, briefly, and heading north to become apprenticed to Patrick Haslam in Middleham Moor, North Yorkshire. He rode his first winner, Perchancer, trained by Haslam, in an apprentice handicap at Southwell on April 9, 2001.
Mulrennan subsequently joined Mick Easterby in Sherrif Hutton, North Yorkshire. On May 1, 2004, he won the Thirsk Hunt Cup on Blue Spinnaker, trained by Easterby, as “a little-known 5lb claimer” and, on May 17, 2006, rode out his claim on the same horse in a handicap at York. Of Blue Spinnaker, Mulrennan said, “…in many ways he was one of the horses who got my career going.” Early career highlights also included his first Pattern winner, Gentleman’s Deal, also trained by Easterby, in the Group 3 Winter Derby at Lingfield on March 24, 2007.
Fast forward to June 16, 2019 and Mulrennan reached the milestone of 1,000 career winners on British soil on Camacho Chief, trained by Michael Dods, in a handicap at Doncaster. Of his long, lucrative association with the County Durham handler, he said, “…I have a great relationship with Michael Dods and we’ve enjoyed many good days together especially with Meccas’s Angel.” Mecca’s Angel provided Mulrennan with his first, and second, Group 1 winner, courtesy of back-to-back victories in the Nunthorpe Stakes in 2015 and 2016. Mulrennan also won back-to-back victories in the Group 3 Palace House Stakes at Newmarket on Mabs Cross, trained by Dods, in 2018 and 2019.
Mulrennan rode his first Royal Ascot winner, Dandino, trained by James Given, in the King George V Stakes on June 17, 2010. He rode over a hundred winners in a year for the first time in 2014 and has since repeated that feat in 2016, 2022, 2024 and 2025. Dods remains his principal benefactor, but he has another long-standing ally in the form of Jim Goldie, who is based in Lanarkshire, Scotland and for whom he has ridden nearly as many winners. On June 17, 2025, the pair combined to win the King Charles III Stakes at Royal Ascot with American Affair. The progressive five-year-old thus became a first Royal Ascot and Group 1 winner for Goldie, who has held a training licence since 1995. Mulrennan quipped afterwards, “The last time I had a Royal Ascot winner [the aforementioned Dandino], I had jet black hair!