Sergei Mazur was born in Sochi in 1994. He was educated at the Art School No 2 (Vladimir Mazur's class) there and then at the Gnessins Music School (Tatyana Berkul's classes) and the Moscow Conservatory (Tatyana Berkul's classes) in Moscow.

He played as a soloist with the Gnessins Virtuosi Chamber Orchestra, the Moscow Conservatory Chamber Orchestra and the Czech Youth Chamber Orchestra. He also took part in the New Names Foundation projects.

He has been the first violin of the RACH-quartet. The group won the First Prize in the String Quartet nomination at the All-Russian Music Competition. In 2018-2020, he was a member of the Russian National Youth Orchestra.

He joined the National Philharmonic Orchestra of Russia in 2020.