Oscar- and Tony-nominated character actor and folk singer Theodore Bikel, who originated the role of Captain von Trapp in “The Sound of Music” on Broadway and starred in “Fiddler on the Roof” onstage in thousands of performances, died Tuesday morning in Los Angeles. He was 91.

In a statement Tuesday, Actors’ Equity Association said it “mourns the passing of our dear friend, our brother and former President Theo Bikel. From the time he joined Equity in 1954, Bikel has been an advocate for the members of our union and his extraordinary achievements paved the way for so many. No one loved theater more, his union better or cherished actors like Theo did. He has left an indelible mark on generation of members past and generations of members to come. We thank you, Theo, for all you have done.”

To some, he is best known for his 1990 appearance on “Star Trek: The Next Generation” as the Russian adopted father of the Klingon Worf.

Bikel did his first bigscreen work in John Huston’s 1951 classic “The African Queen” and Huston’s “Moulin Rouge.” After acting in a series of English films, he did supporting work in two high-profile pics in 1957: historical epic “The Pride and the Passion,” starring Cary Grant, Frank Sinatra and Sophia Loren, and “The Enemy Below,” a WWII submarine thriller starring Robert Mitchum.

He often played Germans or Russians — in his autobiography, Bikel said that his facility with accents resulted in his typecasting “as the poor man’s Peter Ustinov.” But in Stanley Kramer’s 1958 film “The Defiant Ones,” starring Sidney Poitier and Tony Curtis, he portrayed a Southern sheriff pursuing a pair of fugitives — and was Oscar nominated for the role.

Bikel had notable supporting turns in Susan Hayward starrer “I Want to Live!” and the remake of “The Blue Angel.” He played dialect expert Zoltan Karpathy in the 1964 film version of “My Fair Lady” and the captain of the Russian submarine in “The Russians are Coming, the Russians Are Coming,” and he appeared in Frank Zappa’s experimental “200 Motels.”

During the 1950s he appeared on prestigious episodic anthology programs including “Goodyear Playhouse,” “The United States Steel Hour,” “Studio One in Hollywood,” “Kraft Theatre” and “Playhouse 90.” He appeared in an episode of “The Twilight Zone” in 1962, and he guested on “Gunsmoke,” “Mission: Impossible,” “Hawaii Five-O” and “Ironside”; during the 1970s he appeared on “Mod Squad,” “Little House on the Prairie,” “Charlie’s Angels,” “Columbo” and “Fantasy Island.” Bikel had recurring roles in the 1980s on “Dynasty” and “Falcon Crest.”

Onstage, Bikel made his first appearance as Tevye in the musical “Fiddler on the Roof” in 1967 and performed the role more than any other actor (at least 2,000 times — more than Chaim Topol, who starred in the movie version and also appeared as Tevye numerous times onstage). When Topol withdrew from a North American tour of show in 2009 due to injury, Bikel subbed in.

Bikel was president of the Associated Actors and Artistes of America, a federation of trade unions for performing artists in the U.S. including Actors’ Equity and the Screen Actors Guild. He was active in Actors Equity for many years, eventually serving as president in the late ’70s and early ’80s.

Theodore Meir Bikel was born in Vienna but his family fled to Palestine after the Nazi invasion in 1938. He was a busy young man in Palestine and then the new state of Israel, acting while still in his teens — he made his stage debut as the Village Clerk in “Tevye the Milkman” at the Habimah Theater in Tel Aviv in 1943, and the next year he co-founded the city’s Cameri Theater, which went on to become one of Israel’s foremost legit houses. (“Tevye the Milkman” was based on the same source material as “Fiddler on the Roof,” in which Bikel would later star repeatedly.)

In his autobiography he addresses the key moral dilemma of his life: He did not return to Israel to fight in the 1948 War of Independence after departing to seek stage work: “A few of my contemporaries regarded what I did as a character flaw, if not a downright act of desertion. In me, there remains a small, still voice, that asks whether I can ever fully acquit myself in my own mind.”

After making his London debut in “You Can’t Take It with You” in 1948, he played Mitch in “A Streetcar Named Desire” opposite Vivien Leigh and directed by Laurence Olivier; he starred in “The Love of Four Colonels,” Peter Ustinov’s first success as a playwright, in 1951; and he starred in “Dear Charles” in 1954.

Bikel then moved to the U.S. and made his Broadway debut in “Tonight in Samarkand.”

He drew his first Tony nomination in 1958 for “The Rope Dancers” and picked up his second two years later for “The Sound of Music.” Bikel had produced and sang on several albums of Jewish folk songs during the 1950s, and right before “The Sound of Music” was to open on Broadway, Rodgers and Hammerstein wrote the song “Edelweiss” specifically for him to sing and accompany himself on the guitar.

Also in 1959, Bikel co-founded the Newport Folk Festival with Pete Seeger and George Wein. A couple of years later he, with Herb Cohen, opened the Unicorn, L.A.’s first folk coffeehouse. Later they opened a second place, Cosmo Alley, which presented not only folk music but poets and comics including Lenny Bruce. Bikel recorded 27 albums, many featuring Hebrew and Yiddish folk music. Bikel was growing increasingly political and attended the 1968 Democratic Convention as a delegate.

He guested in the ’90s on “Law and Order,” “Babylon 5” and repeatedly on “Murder, She Wrote.” His most recent TV appearance was on an episode of “JAG” in 2003. In 2010 Bikel was nominated for the Drama Desk Award for outstanding solo performance for “Sholom Aleichem: Laughter Through Tears.”

“Theo: The autobiography of Theodore Bikel” was published in 1995 and reissued in 2002. Bikel was also appointed by President Carter to serve on the National Council for the Arts.

In a statement, the Actors’ Equity Association said: “From the time he joined Equity in 1954, Bikel has been an advocate for the members of our union and his extraordinary achievements paved the way for so many. No one loved theater more, his union better or cherished actors like Theo did. He has left an indelible mark on generation of members past and generations of members to come. We thank you, Theo, for all you have done.”

His third wife, conductor Tamara Brooks, died in 2012, but he married again in 2013. Bikel is survived by his fourth wife, Aimee Ginsburg-Bikel, sons Rob and Danny, stepsons Zeev and Noam Ginsburg and three grandchildren.

Donations may be made to The Actors Fund and Mazon – A Jewish Response to Hunger.