Mills, who joins as director of sales and marketing, has spent the past five years at Coral, the third-biggest bookmaker in the UK, after Ladbrokes and William Hill.
Racing UK has been seeking a chief marketer since last summer to drive subscriptions for the fledgling channel ( Marketing, 11 August 2004).
In his new role, Mills' main remit will be to promote the channel during the transition of 200,000 viewers from a free-to-air to a paid-for subscription service. He will report to chief operating officer Andrew Brown.
Racing UK was set up in May last year by racecourses including Goodwood, Epsom and Aintree, which wanted greater control of their media rights.
It was founded following the collapse of the Attheraces channel, launched by a consortium of Arena Leisure, BSkyB and Channel 4. The group struck a 10-year, £307m deal to cover races from 49 of the UK's 59 racecourses.