[1] Vallín was born in Mexico City, where he lived for the first ten years of his life until he moved with his family to Aguascalientes, capital of the state of the same name.

"Wando" won first place in the contest "Valores Juveniles Bacardí" in 1993 in the group category with "Puedo gritarlo frente a ti".

Vallín has recorded four other studio albums Sueños Líquidos (1997), Revolución de Amor (2002), Drama Y Luz (2011), and Cama Incendiada (2015) as well as the Maná MTV Unplugged (1999).

In Amar es Combatir he wrote three songs: the cumbia "Somos Mar y Arena", "Relax", and "Bendita tu Luz".

Sergio, who is considered one of the best Latin guitarists, is an admirer of flamenco, Paco de Lucía and Tomatito, and has become involved in projects outside of Maná.