Markus Maskuniitty began his music studies in the Rauma Youth Band at the age of nine and later studied with Timo Ronkainen at the Sibelius Academy. Among his other influential teachers were Radovan Vlatković and Michael Höltzel.

Maskuniitty is a prizewinner of several international competitions, including the ARD
Competition in 1994. He was named Brass Player of the Year in Finland in 1992.

He joined the Gustav Mahler Jugendorchester as principal horn in 1990. While on tour with the orchestra, Claudio Abbado was impressed by Maskuniitty’s playing and invited him in 1993 to audition for the principal horn position of the Berlin Philharmonic. The position was won by Stefan Dohr, and Maskuniitty became his successor at the Deutsches Symphonie- Orchester Berlin. Maskuniitty moved to Berlin in 1994, after holding the principal horn position of the Finnish Radio Symphony Orchestra from 1991 to 1993. In 1997, he joined the Berlin Philharmonic as principal horn alongside Stefan Dohr, but returned in 1999 to the Deutsches Symphonie-Orchester Berlin, where he remained until 2007. In the summer of 2000, he was also engaged by the Bayreuth Festival Orchestra. In 2007, Maskuniitty joined the Royal Stockholm Philharmonic Orchestra as successor to the legendary Ib Lanzky-Otto. He has also been a member of Stockholm Chamber Brass (2000–2010) and the Berlin Philharmonic Octet.
Maskuniitty has premiered, among others, horn concertos by Jukka Linkola, Harri Wessman, and Jorge Torres Sáenz, as well as a double horn concerto by Andrea Tarrodi. He was appointed Professor of Horn at the Hochschule für Musik, Theater und Medien Hannover in 2000, and today many of his former students play professionally in several European countries.

Maskuniitty’s recordings include a concerto CD (BIS) with the Royal Stockholm
Philharmonic Orchestra and Sakari Oramo (nominated, among others, for the BBC Music Magazine Award in 2020), a recital CD of Nordic-influenced music (BIS), chamber music recordings with Stockholm Chamber Brass (BIS), and the premiere recording of Penderecki’s Sextet (Naxos). In addition, his solo horn playing can be heard on numerous recordings by the Finnish Radio Symphony Orchestra, the Deutsches Symphonie-Orchester Berlin, the Berlin Philharmonic, and the Royal Stockholm Philharmonic Orchestra, including the 1998 live recording of Bruckner’s Fourth Symphony with the Berlin Philharmonic under Günter Wand.