John Patrick Doyle AM (born 9 March 1953) is an Australian actor, writer, radio presenter and comedian best known for his character Rampaging Roy Slaven.

Doyle was born in Lithgow, New South Wales in 1953 into a music-loving, Catholic household with three sisters, Deanna, Cathy, and Jen, and a brother, Tony. His mother was a business woman and his father a railway fettler. He was an altar boy for a time but lost interest in Catholicism with the introduction of contemporary changes in the mass, among other things.

He attended and was a prefect at De La Salle Academy in Lithgow before graduating from the then Newcastle Teachers' College in 1973 with a Diploma of Teaching (Secondary English/History). He completed a Bachelor of Arts degree at the University of Newcastle (NSW) in 1978 before joining the Hunter Valley Theatre Company. Doyle continued to perform while teaching at Glendale High School near Newcastle. After seven years of teaching, he moved to Sydney, where he worked with the Sydney Theatre Company.

Doyle began his radio career in 1985 when his character "Rampaging" Roy Slaven appeared on Triple J's breakfast show every Friday. 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. During that time, he met Flinders University arts graduate and comedian Greig Pickhaver when they worked together as minor characters on the SBS children's series Five Times Dizzy. Pickhaver had similar comedic skills and interests, and had also developed a sporting commentator character called HG Nelson while appearing on the Melbourne radio comedy program Punter to Punter in the early '80s. An amalgam of just about every Aussie sports commentator and race caller who ever lived, HG, like Roy, has seen and done it all and is utterly passionate about truth and honesty in sport.

The team of "Roy and HG" was born when This Sporting Life premiered on Triple J in early 1986. The four-hour (later three-hour) comedy show, improvised live, soon became a cult hit. Over that time Doyle and Pickhaver perfected a unique style that satirises the world of sport and the athletes, the entertainment scene and celebrity in general, in a manner that is simultaneously ruthless and affectionate. As well as their weekly radio show, the duo also made satirical radio "calls" of major annual sporting events including the State of Origin series, the NRL and AFL Grand Finals (known as the Festivals of the Boot, Parts I and II) and the Melbourne Cup, as well as occasional outside broadcasts of TSL performed before live audiences.

In addition to This Sporting Life, Doyle hosted the two-hour mid-afternoon shift on ABC radio station 2BL in Sydney for several years in the late 1980s and early 1990s, earning a loyal following among listeners and demonstrating that he was not only extremely knowledgeable on a huge range of subjects, but was also a superb interviewer. He took over many existing program segments and made them entirely his own, and his regular conversations with guests such as cooking expert Barbara Lowery, Sydney Opera House media liaison officer "Commodore" David Brown (whom he nicknamed "The Salty Sea Dog"), gardening expert Angus Stewart (nicknamed "The Doctor Of The Dirt"), pop music expert and "Sydney Morning Herald" journalist Bruce Elder (nicknamed "The Professor of Pop") and Sydney Morning Herald TV Guide editor Tony Squires, became regular highlights of the show.

Like Graham Kennedy, Doyle specialised in subtly (or blatantly) undercutting the "straight" presentation of such stock segments, and he often veered off on tangents that he found funny or diverting, or introduced ideas which he thought might be likely to get a "rise" from his guest. One memorable thread was his long-running obsession with the source of a supposed "mystery noise" that was reputedly disturbing patrons in the Opera House Concert Hall, and he regularly badgered long-suffering Opera House publicist David Brown for an explanation. The inadequacy of the women's toilets were also a frequent subject of discussion, or more correctly, interrogation, and the "what's on at the Opera House" segments stretched from around 10 minutes to a whole half-hour, through most of which David Brown's characteristic laugh was a highlight.

Although his "Slavenesque" sense of humour often showed through on the 2BL shift, Doyle and Pickhaver were assiduous about keeping their real-life identities and the Roy and HG characters separate (they were rarely photographed) and although Pickhaver often appeared on The Afternoon Programme as HG Nelson, Doyle never performed overtly as Roy, or referred to him in any way. During this period Doyle kept up a hectic work schedule, presenting The Afternoon Programme two hours a day, Monday to Friday, as well as his regular four-hour stint on Saturdays on This Sporting Life and also, at one stage, the first weekly half-hour TV version of the show.