Mari Järvi started her piano studies at the Tallinn Music High School in 1966. In 1977–1982 she studied at the Tallinn Conservatory in the piano class of Virve Lippus. From 1979 to 1995 she worked as an accompanist at the Tallinn Music High School.

Currently she works as a piano teacher and accompanist at the Lahti Conservatory in Finland. She has performed with various soloists in several European countries, including Finland, Sweden, Germany, Austria, Spain, Portugal and Slovenia.
She has also participated as an accompanist in master classes given by many teachers, such as P. Vernikov, A. Chumachenko, Fr. Helmerson, M. Rousi, M. Frischenschlager, B. Kotmel, A. Fischer, and H. Shaham, in Estonia, Finland, the Czech Republic, Slovenia and Germany

Mari Järvi has also participated as an accompanist in several international competitions for musicians. She also performs frequently with her family, husband Teet Järvi and her children, who are all musicians as well.