Dominic Raab claims he is "over the post-traumatic stress disorder" of being a Conservative leadership candidate.
The ex-contender was knocked out of the race after failing to secure the backing of enough of his colleagues in June, but said he had no hard feelings towards the final two.
Mr Raab was in attendance at a head-to-head debate between Boris Johnson and Jeremy Hunt, who both shared their Prime Ministerial ambitions at talkRADIO's headquarters last night.
When asked by talkRADIO's Ian Collins whether he wished he was on the stage, the former Brexit Secretary said he was "just thinking about the two candidates in front of me".
"The defining difference between them [Johnson and Hunt] remains this issue of who could be most trusted to get us out of the EU by the end of October," he said.
"This is the defining issue of this contest and I think, again, it was crystal clear that Boris is the man to deliver."
He continued: "I want Boris to be the Prime Minister because he's got the conviction and resolve to get us out of the European Union."
Despite pledging his support for Mr Johnson in the leadership race, Mr Raab refused to rule out accepting a role with Jeremy Hunt if he were to become the next Conservative leader.
"I don't get into the flouncy thing about saying I won't serve under X and Y," he added.