Born in country Victoria in the late 1950s, Walker began as a journalist for community radio and magazines in the late seventies, before publishing his first book, Inner City Sound, in 1981 (a revised and expanded new edition was published in 2005). His third book, Highway to Hell: The Life and Times of AC/DC Legend Bon Scott (1994) was a best seller in Finland. He is also the author of Stranded: The Secret History of Australian Independent Music 1977-1991 (1996). Buried Country, which is a history of Aboriginal country music is his sixth book, followed by 2005's Golden Miles: Sex, Speed and the Australian Muscle Car.
He has also worked at ABC Television on the documentary series, Long Way to the Top and Love is in the Air, "Sex with Apes", as well as co-hosting the live music program Studio 22.