Pēteris Endzelis began learning to play the oboe in the Emīls Dārziņš Music School with Uldis Urbāns, moving on to Liepāja Music College, followed by oboe studies in Jāzeps Vītols Latvian Academy of Music under Vilnis Pelnēns.
From 1998 to 2005 Endzelis was the principal oboist in the Liepāja Symphony Orchestra. Since 2001 he has been the principal oboe in the Latvian National Opera and Ballet. As of 2011 he is also the lead oboist in the Chamber Orchestra Sinfonietta Rīga, directed by Normunds Šnē.
He has performed as a soloist with Gidon Kremer and the Chamber Orchestra Kremerata Baltica, with Marta Sudraba in some of the most famous European concert venues, as well as with the Liepāja Symphony Orchestra and the Latvian National Opera and Ballet orchestra. He has also performed in the David Oistrakh Festival in Pärnu.
Pēteris Endzelis has worked with such esteemed conductors as Mstislav Rostropovich, Vladimir Ashkenazy, Mariss Jansons, Andris Nelsons, Neeme Järvi, Paavo Järvi, Heinz Holliger, Krzysztof Penderecki, Olari Elts, Andris Poga, Cornelius Meister etc.
He regularly collaborates with the Nordic Symphony orchestra, the Tallinn Chamber Orchestra and the Latvian National Symphony Orchestra.
In 2010 Endzelis received the Latvijas Gāze Annual Award as the Best Orchestra musician.