Mr Walker, 72, renowned for his remarkably enthusiastic style, has signed a two-year deal with ITV, which this summer bought up rights to the live coverage of Formula One.
Speaking from Estoril in Portugal, where he commentated for the BBC last weekend, Walker - who has described every Grand Prix since 1978 - said: "Motor racing is my passion and my life. Until very recently I saw that stopping, but thanks to ITV it is not and I am absolutely delighted." ITV's plans for Formula One coverage were "very impressive".
ITV has secured the rights to broadcast motor racing for five years with a bid reported to have been in the region of pounds 70m. Capturing the services of Mr Walker, who is widely regarded as the face and voice of Formula One, completes the picture.
Working for independent television will not be a new experience for the long-time BBC man. During the late Fifties and early Sixties he worked as a freelance, commentating on motorcycle scrambles.
ITV's network director Marcus Plantin said: "I am delighted to be able to end recent speculation and welcome Murray to ITV. Public support and affection for him is enormous."
The news will delight members of the Murray Walker fan club (Slogan: "Unless I'm very much mistaken ... I'm very much mistaken"). Although frequently mocked for his excitability when a major catastrophe occurs on the track - such as the occasion when flames engulfed the Dutch driver Jos Verstappen in the German Grand Prix - Walker's strident tones have become legendary .
His high-rev style currently features in a pizza advertisement in which he goads driver Damon Hill to near violence.Reuse content