In 2001, Mariliis Valkonen graduated in music theory from the Tallinn Georg Ots Music High School where she also studied composition with Lembit Veevo. In 2005, she got bachelor degree in composition from the Estonian Academy of Music as a student of Prof. Eino Tamberg. In 2012, Mariliis obtained master degree at the Estonian Academy of Music and Theatre with Helena Tulve. In 2004 and 2006, Mariliis Valkonen took part in the International Workshop for Young Composers in Dundaga, Latvia.
Works of Mariliis Valkonen have been performed by pianists Mati Mikalai and Sten Lassmann, NYYD Ensemble, Ensemble U:, Estonian National Symphony Orchestra, Tallinn Chamber Orchestra, Chamber Choir Collegium Musicale. Her music has been presented at the Estonian Music Days Festival, Glasperlenspiel Festival and Estonian Academy of Music and Theatre Autumn Festival. She has been awarded at the composition contests of the Estonian Academy of Music and Theatre Autumn Festival (1st prize for ensemble work The Chance of the Journey, 2005), her mixed choir song “Way to Home” deserved 1st prize at the Estonian patriotic choir song contest in 2004 and was performed at the Tenth All-Estonian Youth Song Festival in 2007. Valkonen’s piano work talsu street got the 1st prize at the student composition competition of the Estonian Music Days Festival 2005, The Detective for three sopranos and percussion was awarded the Composer Prize at the Estonian Music Days Festival 2005 and Takeoff for mixed choir and string quartet Composer Prize at the Estonian Music Days Festival 2013.