Diana Ketler was born in 1971 in a well-known musician family in Riga. She began her piano studies at the age of five in Emīls Dārziņš Music School. In 1993, Ketler graduated with honours from the Latvian Academy of Music. She then studied in Salzburg in 1992–1994. She continued her studies in 1994 in London, where she graduated in 1996 with a RAM diploma.
Ketler had her concert pianist debut at the age of 11 with the Latvian National Symphony Orchestra, led by Vassily Sinaisky. She has since performed with several orchestras as a soloist and she has performed at many festivals. She has collaborated with several famous musicians, and she is a member of the ensemble Raro. She has performed the premieres of composers from the Baltic countries.
Diana Ketler has been a professor of piano at the Royal Academy of Music in London since 2003. She gives master’s classes all over the world. She has also been the artistic director of the festival Chiemgauer Musikfrühling since 2004.