He became principal of the London Symphony Orchestra (LSO) in 1986 following the footsteps of the late Jack Brymer until he ended his tenure in 2019.
During his orchestral career he maintained his place on the worldwide solo concert platform alongside an active role in the field of chamber music.
He has worked with some of the most distinguished individuals in the world of chamber music such as Alfred Brendel, André Previn, András Schiff, Lynn Harrell, Stephen Isserlis, Emanuel Ax, Hélène Grimaud, Sylvia McNair, Edita Gruberova and with the late Vlado Perlemuter and George Malcolm.
In April of 2019, Marriner joined the Los Angeles Chamber Orchestra to perform Mozart's Clarinet Concerto in A Major.
He has continued as a chamber music partner with Magdalena Kozena and Sir Simon Rattle to participate in a series of concerts traveling about Europe in 2022.