Marrero got her start as "Gloria" on the Disney Channel kids show Kids, Inc about a group of neighbourhood ghetto kids who rose to local fame by singing staged productions at a corner malt shop. She was quickly snagged by CBS Records as a potential, Madonna-esque pop star. Her first album, Martika, spawned the number one hit of 1988 "Toy Soldiers", but was, as is often the case with American pop stars, an even huger success abroad. (She had foreign hits with "Water", "More Than You Know", "I Feel the Earth Move" and "Alibis".) In 1991, she was approached by Prince and became one of the so-called "Prince Protégés". Her second album, Martika's Kitchen, was an American flop (but for the radio favourites "Love...Thy Will Be Done" and the title track.) However, the album was again a huge success abroad, though on a lesser scale, spurning hits with the songs "Coloured Kisses" and "Temptation". However, it faded fast on the charts and went out of print.
Martika attempted to revitalize her acting career by playing lounge singer/undercover cop Delia Mendez on the early 1990s cop show Wiseguys, but the part was a temporary one and eventually she faded from the public eye around 1993.
During the 2000 explosion of Latin pop music Martika attempted to regain interest by singing backing vocals on various projects and contributing lyrics, but she failed to grab any major label attention. Instead she built a web site in 2001 (martika.net) for her fans, and released a remix of a newly self-recorded song called The Journey. The song, however, garnered only 5000 hits as a free download on mp3.com's music service. Eventually the web site shut down and Martika seemingly faded, once again, into Hollywood oblivion.
In 2003 Martika joined forces with a musician named Michael Mozart to form the band "Oppera".