The presenter shook his stuff for charity, raising £643,336 by the end of the Day of Dance.
O'Leary was joined by the likes of Caroline Flack, Geri Halliwell, The Kaiser Chiefs and Sir Terry Wogan during his gruelling challenge.
He's on his way @BBCOne #dancingdermot pic.twitter.com/GYY1WfXFaj
— Red Nose Day (@rednoseday) March 13, 2015
He completed his marathon dance at the London Palladium live on BBC One at 7.20pm.
Asked by presenter Lenny Henry about the balls of his feet, an exhausted O'Leary said: "They've seen better days my friend... every ball in my body, in some shape of form, has been through a hard time."
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Speaking earlier to BBC News, he said: "I'm never going to dance again in my whole life. I swear."
Now is the time.
If you've loved #dancingdermot - really loved it - please text DERMOT to 70005 right now then RT x pic.twitter.com/8soQQ0yyPe
— Red Nose Day (@rednoseday) March 13, 2015
He added: "The feet are fine until anyone asks me that question, and then I think about them!
"But they're okay. My knees are sore."
To donate to Comic Relief, please visit the Red Nose Day website.
