Constantine Maroulis appeared as a finalist on the reality television show American Idol during the show's 2005 season. A 2002 graduate of the Boston Conservatory, Maroulis is a Greek American from New York City and makes a living singing, acting, and writing, including appearing in the national tour of the Broadway show Rent, playing the role of "Roger Davis." He is also the lead singer of the rock band Pray for the Soul of Betty. Contrary to what was portrayed on the reality TV series, he did not quit his band, only took a temporary leave of absence to join American Idol, and returned after he was voted off. His rendition of the Queen classic "Bohemian Rhapsody" earned him the praise of judges, including Simon Cowell The performance also attracted the notice of Queen guitarist Brian May, who invited Maroulis to record a studio version of "Bohemian Rhapsody" for the band's 30th Anniversary tribute album, Killer Queen.

In August 2001, he played Hedwig in Hedwig and the Angry Inch. He was also the winning contestant on the dating show Elimidate on location in Boston before he auditioned for American Idol. Other notable theatrical perfomances include roles in Tango 'til They're Sore (Oleg), Macbeth (Malcom), Jesus Christ Superstar (Judas, Jesus).

On October 12, 2001, Maroulis appeared in the episode entitled "Stolen" (Season 3, Episode 46) of Law and Order: Special Victims Unit He has also appeared in several independent films (i.e, The Strangler's Wife) and provided the voice of Mechanic #1 in Warner Brother's Japanese animated series, AstroBoy.

 
Constantine on Elimidate.On April 27 2005, Maroulis was voted off American Idol after he performed Nickelback's "How You Remind Me" during 2000's music week. His sixth-place ouster caused much shock and outrage from fans and is noted as having made Paula Abdulcry.

On May 10 2005, Pray for the Soul of Betty, through a distribution deal made with Koch Entertainment, released their self-produced and self-titled CD on their own label, Baby Julius Productions. Maroulis can also be heard on the American Idol Season 4: The Showstoppers CD singing "My Funny Valentine", a performance which earned high praise during Musicals theme week.