Played piano for musical group, The Revuers (Adolph Green, Betty Comden, Judy Holliday), at Village Vanguard, New York
Worked at Harms-Remick music publishing company, writing popular arrangements under pseudonym, Lenny Amber (Bernstein in English) (date approximate)
Composed first symphony, "Jeremiah" (Symphony No. 1)
Hired by Artur Rodzinski as assistant conductor of New York Philharmonic
Substituted for Bruno Walter as conductor of New York Philharmonic concert on November 14
Composed first ballet score, "Fancy Free"
Scored first Broadway musical, "On the Town
Made principal conductor of New York Philharmonic
First film credit (song composer), "On the Town"
Was first American-born conductor to be engaged by La Scala in Milan, Italy
First original film score, "On the Waterfront"
Made co-director of New York Philharmonic (with Dimitri Mitropoulos)
First American-born director of New York Philharmonic
As Charles Eliot Norton Professor of History at Harvard, lectured on linguistics as applied to musical analysis
Honored with the renaming of 65th Street between Broadway and Amsterdam Avenue as Leonard Bernstein Place