Captain Jack was a musical duo, specializing in Eurodance music, originating from Germany. Its members (since 2000) were Francisco Alejandro Gutierrez (stage name: Franky Gee, now deceased), and Sunny. The original female vocalist on the group's debut in 1995 was Liza Da Costa, replaced in 1999 by Maria Lucia 'Maloy' Lozanes, who was replaced by Ilka-Anna-Antonia Traue (stage name: Illi Love) in 2001.

The gimmick to Captain Jack's music (and Franky Gee's persona) was that of military training. Franky's costume consisted of a stylized military general's uniform, with a red hat based on that of the US Marines. Gutierrez chose this gimmick because of his service in the United States Army, a career he despised but was forced to follow when he was strapped for cash. After ending his time in the US Army, Gutierrez remained in Germany, where he was last stationed, and began a recording career under the name "Westside".

While recording music under that name, he proposed the idea of a dance track based on a drill routine. That idea became his style: songs about peace and love in the style of a military regime, in protest against his years in the US Army. The hat—a US Marines "barracks cover" hat, in the color scheme evoking the Soviet Red Army—further protests the idea of the military, while symbolizing the idea of national unity.

The group has earned 19 gold and platinum records throughout Europe. Fans of the Konami arcade game Dance Dance Revolution know them from the numerous songs that, through the Dancemania series of albums, have been used in the game series. The group's music was also featured in other Konami music games such as beatmania and Dance Maniax.

The future of Captain Jack suddenly came into doubt when Gutierrez suffered a cerebral hemorrhage while walking with his son in Spain on October 17, 2005. Doctors predicted that the damage was fatal, and Gutierrez died on Saturday October 22, 2005 after spending five days in a coma. The band's future without frontman Gutierrez (also referred to by many fans as "Captain Jack") is currently unknown.

As stated by an e-mail from Beatdisaster, December 7, 2005: Proceeds of sales (from the "Greatest Hits" album) to the (22.10.05) deceased artist "Franky Gee" (Francisco Gutierrez) go in favor of his son & Rapper of the same name, Francisco (Franky). In 2006, his career as "Captain Jack Junior" starts and the musical inheritance begins.