Dore Schary, 74, a noted writer and producer of Hollywood and Broadway hits who also had a reputation for steadfast support of liberal causes and candidates, died Monday at his home in New York city, He had cancer.

As a film script writer, he won an Oscar for "Boys Town," which appeared in 1938 and starred Spencer Tracy. In all, he wrote the scripts for more than 40 films. As a producer, he headed the production of low-budget pictures for Metro-Goldwyn-Mayer, was vice president of production for RKO, and then returned to MGM as head of all production. At one time he was known as "the boy wonder of Hollywood."

Fired from MGM as the result of a struggle for control of the company in 1956, he turned his hand to playwriting. The result was "Sunrise at Campobello," which was based on Franklin D. Roosevelt's struggle against poliomyelitis. When it appeared on Broadway in 1959, it won five "Tony" awards and was one of the major successes of that time. The play later was made into a successful film.

In politics, Mr. Schary was a lifelong liberal. He was an early supporter of Gov. Adlai E. Stevenson of Illinois, the Democratic presidential nominee in 1952 and 1956. He undertook this at a time when the powers of Hollywood were concerned with maintaining a conventional conservative position in the face of the anticommunist excesses of the early Cold War years.

In 1947, Mr. Schary's liberalism was put to the test in connection with hearings by the House Un-American Activities Committee investigations of alleged communist infiltration into the film industry. The result of the hearings was the blacklisting of "The Hollywood 10," all of whom had refused to state to the committee whether or not they had been members of the Communist Party.

The film industry adopted a policy of refusing to hire any of "The 10" until they had purged themselves of the contempt citations issued against them by the House committee. This position was worked out at a conference of studio heads at the Waldorf-Astoria Hotel in New York City.

Mr. Schary, who was one of those present, maintained that no one should be denied the right to work merely for exercising a constitutional right, such as that of political association. When his peers in the industry refused to go along with this, Mr. Schary decided not to resign, but to work within the system for a change in the policy.

The result was that he was attacked by both the left and the right.

But it did not harm his career in Hollywood. The films he helped produce over the years are some of the most admired as well as some of the most entertaining that the industry has ever issued.

They include "Joe Smith, American," "Journey for Margaret," "Lassie Come Home," "The Farmer's Daughter," "The Setup," "The Window," "The Boy With the Green Hair," and "Battleground."

Other Schary credits were "Go for Broke," "Bad Day at Black Rock," "The Swan," "Blackboard Jungle," "Lili," "An American in Paris," "Seven Brides for Seven Brothers," "Executive Suite," "Intruder in the Dust," "The Red Badge of Courage," "Ivanhoe," "Father of the Bride," and "Tea and Sympathy."

In 1956, the last year that Mr. Schary headed production at MGM, the studio's pictures earned 31 nominations for Academy Awards.

For several years afterwards, he continued to produce -- and sometimes to direct -- films on an independent basis. He also continued his career on Broadway.

In "Heyday," an autobiography that was published last year, Mr. Schary, a scholarly-looking six-footer, said that "in terms of life styles, I really had nothing in common with the other studio heads . . . I never was a big gambler. I didn't go to the race track, and I didn't have the energy or interest to keep two or three women on the side."

He made his career with such giants of the industry as David O. Selznick, Howard Hughes and Louis B. Mayer. In "Heyday," he had nice things to say about all of them.

"You show a man's weaknesses and terrible faults," he said in discussing the book, "but you can also show he was a person."

Dore Schary was born in Newark, N.J. on Aug. 31, 1905. His parents, Herman Hugo and Belle (Drachler) Schary, named him Isadore. He took the name Dore (pronounced Dor-ree) by dividing his first name in half and dropping the first part.

He grew up in Newark and New York City, where the family had a successful catering business. He became interested in writing while still a youngster, worked briefly for a newspaper, and then went back to Newark Central High to complete his education.

He began his theater career with a stock company in Cincinnati. His first appearances on Broadway were in bit parts in "Four Walls," which starred Paul Muni, and in "The Last Mile" (1928), starring Spencer Tracy.

In 1932, he went to Hollywood and got a job as a $100-a-week screenwriter at Columbia Pictures. His success at that craft was almost immediate and he wrote for all the major studios.

In 1941, Louis B. Mayer hired him to head the production of "B" pictures on the MGM lot. From 1943 to 1946, he was a producer for David O. Selznick. In 1947, he became vice president for production of RKO, but ran afoul of the mercurial Howard Hughes when the billionaire acquired control of the company. From 1948 to 1956, he was the production chief of MGM.

Mr. Schary's other activities included the national chairmanship of the Anti-Defamation League of B'nai B'rith, an honorary vice presidency of United World Federalists, and the presidency of the Dramatists Guild Fund. He was a member of the Screen Writers Guild, the Screen Producers Guild, the Academy of Motion Picture Arts and Sciences, and the League of New York Theaters.

Survivors include his wife of 47 years, Miriam, of New York City; two daughters, Jill Schary Robinson of Westport, Conn., and Joy Stashower of Los Angeles; a son, Jeb, of St. Louis, Mo., and seven grandchildren.