The 21-year-old, who finished second to James Arthur in this year's series, performed 'Silent Night' for the supermarket chain's festive campaign.
Douglas said that the 80-second clip, launched this weekend, is meant as a thank you to the colleagues and customers who supported him during his time on The X Factor.
ASDA has also released a behind-the-scenes video showing the recording of the track.
Douglas's job at ASDA was heavily referenced during The X Factor, with his mentor Nicole Scherzinger even visiting a store and donning the famous uniform.
ASDA, meanwhile, renamed a Chinese takeaway dish 'Chicken Jahmene' in support of the singer and donated £10,000 to Women's Aid, a charity working to end domestic violence against women and children, after learning of how Douglas and his mother suffered at the hands of his father.
Photo gallery - X Factor 2012 after party: