Doyle commenced his radio career in 1986, when he and Greig Pickhaver created the characters of "Rampaging" Roy Slaven and HG Nelson. Loosely based on classic TV sporting commentators such as Rex Mossop, Doyle created Slaven as a larger-than-life persona, an utterly opinionated, impossibly talented "sporting everyman" who has represented Australia in every field, won innumerable Melbourne Cups on his ageless mount Rooting King, is on intimate terms with every sporting celebrity (including many top racehorses), as well as film and music stars, politicians and other leaders of society around the world, yet who retains the "common touch" and stands for Australian manhood, fairness, and honesty. Slaven is the name of a well known family from Doyle's home town, Lithgow.