Johns, who competed on the Fox reality singing competition's seventh season in 2008, passed away on Friday from a blood clot originating in his ankle, Us Weeklyreported.
"Michael Johns was an incredible talent and we are deeply saddened by the news of his passing. He was a part of our American Idol family and he will be truly missed. Our hearts and prayers go out to his family and friends during this difficult time," Fox, American Idol and its production companies said in a statement.
Johns is survived by his wife Stacey Vuduris, whom he wed in 2007.
Johns released an album titled "Hold Back My Heart" in 2009 and followed it up with an Extended-Play Single called "Love and Sex" in 2012.
"I just heard the very sad news that Michael Johns has passed away. A truly great guy. Rest in peace Michael," Cowell tweeted Saturday.
"So sad. Too soon. Thank you for sharing your talents with us. RIP Michael Johns," Jackson wrote on the same day.
Added Abdul, "Heartfelt condolences to the family of [Michael Johns]... He will be missed... I'm heartbroken over the loss of [Michael]. His enormous talent, gigantic heart & infectious personality will live in my heart forever."