However, in 1969 he switched sides and joined the establishment, BBC Radio One. It was not the easiest of relationships.
He was, he said, accused of being “too into the music”. He would pepper his shows with album tracks and songs outside the approved playlist.
When he championed Walk on the Wild Side, Lou Reed’s song about sex, drugs and transgender bohemia, his BBC boss had questions. It only stayed on the playlist because they had never encountered the phrase “giving head”.
Walker also loved Bruce Springsteen and the Eagles; Chirpy, Chirpy Cheep, Cheep, not so much.
The cheery, cheeky sound of 70s mainstream radio was not his thing. At one Radio One event, he and Peel remembered watching, stunned, as fans of the Bay City Rollers brought chaos.
“Bay City Roller fans were jumping into the lake to be near their idols who were in a boat. John Peel turned to me and said, ‘Johnnie, take note, this is one of the most bizarre sights you will ever see’.
“And then speeding into view came Tony Blackburn in another boat, being steered by a Womble.”