He was born in Algeria, which he left in 1962, working at Côte d'Azur where he served as a DJ. He is a singer in the surf pop group Menton: Les Radis Beurre. Their only single is today lost to time. Lenoir began on France Inter as a music programmer on José Artur's Pop-Club. He worked through the late 1970s presenting the rock program Feedback, and continued on with it into the 1980s. One of his most remembered broadcasts in this period was on 18 December 1979, an airing of a Joy Division concert from Bains-Douches.
The program was cancelled after one season and Lenoir transferred to Europe 1. He also appeared on the television program Les Enfants du rock.
With the launching of the magazine Les Inrockuptibles, the presenter acquired the eternal trust of his audience, and created a program in which he found his true style of "music unlike all others", and his greatest audience. The broadcast lent its name to the magazine. His radio program was called C'est Lenoir (This is Lenoir), and was last broadcast on July 1, 2011.
On August 25, 2011, he announces he has chosen between "life outside" and "music unlike all others" and leaves France Inter. He is currently retired in Biarritz, France.