He trained as a violinist at the Jāzeps Vītols Latvian Academy of Music, as a double-bass player with Vitautas Sereikaan at the Lithuanian Academy of Music and Theatre, and played in several Latvian orchestras before entering the State Conservatory in Vilnius in the neighboring Lithuania to study composition with Valentin Utkin, as he was prevented from doing this in Latvia due to Soviet repressive policy toward Baptists.

Vasks' early style owed much to the aleatoric experiments of Witold Lutosławski, Krzysztof Penderecki and George Crumb.

Later works included elements of Latvian folk music, such as his gentle and pastoral cor anglais concerto (1989).

Vasks feels strongly about environmental issues, and a sense of nature both pristine and destroyed can be found in many of his works, such as the String Quartet No.

Vasks was the recipient of the Vienna Herder Prize of the Alfred Toepfer Foundation in 1996, as well as the Baltic Assembly Prize for Literature, the Arts and Science, and the Latvian Grand Music Award in 1997, the latter for his first violin concerto Tālā gaismā ("Distant Light") (1996–97).