"Today was the best day of my life," Young told People. "Diana and I are in it forever. She's my best friend."
The couple exchanged vows that they had written themselves. After the ceremony, which took place at the Luxe Sunset Boulevard Hotel, they walked back up the aisle together to Led Zepplin's "All of My Love."
The couple penned an original song, called "I Do," which was played for their first dance. Guests at the ceremony included other Idol finalists Elliott Yamin, Michael Johns and Kevin Covais, as well as DeGarmo's co-stars from The Young and the Restless.
Young, 32, appeared on the fifth season of American Idol, while DeGarmo, 25, was a runner-up in Season 3. Young proposed to DeGarmo last year on live TV during Idol's Season 11 finale.