Lewis Carnie, who had been the boss of Radio 2 since it was launched in 1967, announced his departure on Friday.
Mr Carnie admitted that when he took on the role, he thought that the station would grow in popularity as it did for previous DJs such as Chris Evans and Jeremy Vine.
However, as the station has seen a decrease in listenership - making it one of the most diminished mainstream radio stations in Britain - Mr Carnie has decided to step down.
His exit follows that of Chris Evans, who left the station last October after just 12 months in the job and was replaced by Zoe Ball.