Martin began his career at age thirteen with the all-boy pop group Menudo.After five years with the group, he released several Spanish-language solo albums throughout the 1990s.

In late 1999, after releasing several albums in Spanish, Martin performed "The Cup of Life" at the 41st Grammy Awards show, which became a catalyst in bringing Latin pop to the forefront of the U. Since its release, the song has sold over 8 million copies, making it one of the best selling singles of all time.

His other studio albums include: Me Amarás (1993), A Medio Vivir (1995), Vuelve (1998), Sound Loaded (2000), Almas del Silencio (2003), Life (2005), Música + Alma + Sexo (2011) and A Quien Quiera Escuchar (2015).

His parents divorced when he was two years old and Martin spent much of his childhood shifting between his father's home in the suburbs of University Gardens, a suburban middle-class neighborhood of San Juan, and his paternal grandmother's house nearby.

He began singing at age six, using wooden kitchen spoons as pretend microphones; he often interpreted songs by Menudo as well as English-language rock groups such as Led Zeppelin, Journey, and REO Speedwagon.

Martin later reflected on his time spent with his family as a child: "Every time I find myself in front of an audience, be it twenty people or one hundred thousand, once again I feel the energy that consumed me back at the family gatherings of my youth." After discovering a newspaper advertisement about auditions for commercials with his father, nine-year-old Martin began appearing in Puerto Rican television commercials for products such as soft drinks, toothpaste, and fast-food restaurants.

After achieving a small amount of fame in Puerto Rico for his work in television commercials, Martin auditioned for membership in Puerto Rican boy band Menudo.Although the executives enjoyed his dancing and singing at his first two auditions, Martin was rejected because he was too short.During this performance, he inadvertently disobeyed the choreography by walking around the stage when it was planned that he would stay still, and was chastised by the band manager after the show: "The mistake was such a big deal that from that moment on, never again did I move when I wasn't supposed to move...That was the discipline of Menudo: You either did things the way you were told or you were not part of the group." Although Martin enjoyed traveling and performing onstage with Menudo, he found the band's busy schedule and strict managing to be exhausting and later reflected that the experience "cost" him his childhood.Martin returned to Puerto Rico to graduate from high school, and thirteen days after turning eighteen, he moved to New York City to celebrate his financial independence; since he was a minor during his time as a member of Menudo, Martin was not allowed to access his own bank accounts.He was accepted into New York University's Tisch School of the Arts, but months before classes began, Martin dropped out and moved to Mexico City to perform in the play Mama Ama el Rock (Mom Loves Rock).