Marin is the Manager of the George Enescu Philharmonic, the Founder of the Violoncellissimo Ensemble and the Romanian Youth Orchestras. In 1999, he founded the Enescu and World Music International Festival in Sinaia and between 2015-2022 he was Manager of the Romanian Youth National Art Center. He has also been a Cello Professor at the National University of Music Bucharest since 1992.

During 1983-2014 he was Soloist in Residence of the George Enescu Philharmonic and performed intensely, both in Romania and throughout Europe, Asia and America, with great conductors, such as Ghennadi Rojdestvenski, Sergiu Comissiona, Cristian Mandeal, Lu Jia, Nanse Gum, Horia Andreescu, Antoni Ros Marba, Mendi Rodan, Misha Katz, Jean Périsson. He has performed in various chamber ensembles with prestigious artists, such as Valentin Gheorghiu, Vladimir Orlov, Radu Aldulescu, Viktor Tretyakov, Ilia Grubert, Mihaela Martin, Mirel Iancovici, Silvia Marcovici, and Jeremy Menuhin. He was also member of the Pro Arte Trio and collaborator of the Voces Quartet.

Marin Cazacu has won international cello competitions in Geneva, Markneukirchen, Leipzig, Bologna, Belgrade, and also performed for several classical music record labels, such as Electrecord, Olympia, BMG and AIX Records.