Young auditioned for American Idol in Denver, wearing a tuque beanie and singing a rendition of Westlife's "Swear It Again" and was unanimously passed on to the next round. American Idol judges Paula Abdul and Randy Jackson approved his entry, with Jackson noting that Young was one of the best singers he had seen audition. Simon Cowell disagreed with Abdul and Jackson but also approved Young, with a small "yes". He was introduced as Brett Young, with the name 'Ace' marked in quotations. Later, he told them he preferred to be called Ace, and the quotes were removed from his credits.

On April 4, the fourth week of the finals, was a designated country songs theme with Kenny Rogers. Young sang "Tonight I Wanna Cry," and received fairly positive reviews. Jackson said it was living proof that Young was single, and Abdul said the song was perfect for his range and that he sang an adequate rendition of a contemporary country music hit. Cowell thought Young had made a good song choice.