The ceremony took place at the Luxe Sunset Boulevard hotel Saturday evening, People reported.
"Today was the best day of my life," Young, 32, told People. "Diana and I are in it forever. She's my best friend."
About 250 people attended the wedding, including fellow Idol finalists Elliot Yamin, Michael Johns and Kevin Covais, as well as some of DeGarmo's costars on "The Young and the Restless," including Christian LeBlanc and Tracey Bregman.
"This was the best way to start the chapter of my life as Mrs. Young," DeGarmo tells People. "I'm over the moon with joy and happiness about our wonderful wedding. I can't wait to spend my life with my husband!"