The 21-year-old wildlife conservationist is part of the current US series of the dance contest, and he hailed both his parents during Tuesday's Dedication Night episode as he performed a contemporary routine set to Phil Collins' You'll Be In My Heart.
"She's an absolute hero to me, because I was two when I lost dad," Irwin said during his intro package.
"As I got older, (I) started to realise just how hard it would have been for her to be there for us, and all the while continue dad's legacy that her and dad built together."
He started to cry, insisting he's "never been able to capture the feeling of gratitude I feel for it".
"At every milestone when I just wished that my dad was there, she was there. And that was enough."
Terri joined her son in the rehearsal room, and told him and it was and his sister Bindi who helped her cope with the heartbreak after the Crocodile Hunter legend died aged 44 in 2006.
"After we lost Steve, it was difficult to smile again. For quite a while," she said.
"So for him to say, 'You lifted me up,' honestly, it was the opposite. Because of them, I could get up every morning. Every day I'm a proud mama."
After the routine judge Derek Hough, who was a professional on the show and danced with Bindi 10 years ago when she won Dancing With The Stars, struggled to talk through tears.
Irwin told viewers and the audience that his dance was for his mother, as well as "all the mums out there who don't get the recognition they deserve".
"This is for the single parents who work so hard every day to put one foot in front of the other," he added.
"It's for anyone who's lost, someone who feels lost - keep going. And if you can, go call your mum and tell her that you love her."
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