German linguist and cultural expert, musician, educator, charismatic teacher, translator; linguistic consultant for culture, art, and medicine. Authored 9 books dedicated to teaching the German language and Germanic cultures, and co-authored Polish-German and German-Polish dictionaries published by Langenscheidt and Berlitz. Co-authored "Learn German with Steffen" (book with CD) which was later dubbed the most prestigious Polish project for German learners by the Institute for Theory of Languages and Language Acquisition at the University of Warsaw.

Worked with the Polonia Society (Polish Community) as a teacher of Polish language and culture for German-speaking students of Polish descent. In this capacity, Mariusz led a group of children and adolescents to win the 1st place in the worldwide "I know the homeland of my ancestors" Polish language and culture competition.

At the “Bednarska” school network in Warsaw he is known for designing an original teaching program and method of vertical language teaching through culture, “German XL”. The program has been is endorsed by the government of the Federal Republic of Germany and the German UNESCO Commission. For many years, Mariusz co-designed and co-organized the “Young Berlin” cultural and scientific seminars held in Berlin for Polish youth.

The centre of his professional interests are the contrasting, cognitive, and intercultural approaches. An active promoter of Polish culture in German-speaking countries. For over 30 years he has been involved in the Polish-German dialogue, historical education, and education for peace.

Founder, owner and managing director of the "Sar Sargsyan Cultural Entertainment" Artistic Agency, and co-creator and managing director of the VISTULA SOUNDS International Festival and Vocal Competition Ciechocinek. Kujawsko-Pomorskie.