The 46-year-old has revealed how his lifetime ambition had been to front RTE's flagship chat show, but he was passed over for the job.
"I idolised Gay Byrne and The Late Late Show. I would love to do that. That was my dream and I aspired for that. I suppose you wouldn't even get as far along the broadcasting ladder if you didn't aspire to something else. I mean, who becomes a priest not wanting to be Pope?" he said.
However, the Mooney Live presenter described how he was pragmatic and knew how decisions were made.
"It can basically be a series of management at the top who decide you're not right for this now. It's like the old thing: he's too fat, he's too tall, he's too short, he's too thin or too good, we want someone who's not too good.
"You hear all these things all the time and I'm sure anybody who puts themselves in the entertainment industry in any shape or form experiences the same thing and they can never quite figure out why did I not get that," he said on Ryan Tubridy's 2fm radio show yesterday.
But asked by Tubridy what are you 'too' ? Mooney replied: "I'm too gay... I don't know to be honest with you. I have no idea. "
He added that he did congratulate Tubridy when he got the same job in 2009.
Famously outed by comedian Des Bishop during an interview with Ray D'Arcy in 2006, the wildlife presenter said he also found it irritating to be constantly asked about his private life during interviews.
He added: "Is David Attenborough married? I have no idea. I have never once heard him asked that question on Graham Norton, or Jonathan Ross' chat show, or on any TV shows..."
Secrets Of The Irish Landscape airs on RTE1 at 6.30pm on Sundays.