Lear was born in New Haven, Connecticut, the son of Jeanette (née Seicol) and Herman Lear, who worked in sales. He grew up in a Jewish home and had a Bar Mitzvah. Lear went to high school in Hartford, Connecticut and subsequently attended Emerson College in Boston, but dropped out in 1942 to join the United States Army Air Forces. During World War II, he served in the Mediterranean Theater as a radio operator/gunner on Boeing B-17 Flying Fortress bombers with the 772nd Bombardment Squadron, 463rd Bombardment Group (Heavy) of the Fifteenth Air Force. He flew 52 combat missions, for which he was awarded the Air Medal with four Oak Leaf Clusters. Lear was discharged from the Army in 1945. He and his fellow World War II crew members are featured in the book "Crew Umbriago" by Daniel P.Carroll (tail gunner), and also in another book: 772nd Bomb Squadron: The Men, The Memories by Turner Publishing Company.
In 1954, Lear was enlisted as a writer hoping to salvage the new Celeste Holm CBS-TV sitcom, Honestly, Celeste!, but the program was canceled after eight episodes. During this time, he became the producer of NBC-TV's The Martha Raye Show, after Nat Hiken left as the series director. In 1959, Lear created his first television series starring Henry Fonda, a half-hour western for Revue Studios (now Universal Media Studios) called The Deputy.
Starting out as a comedy writer, then a film director (he wrote and produced the 1967 film Divorce American Style and directed the 1971 film Cold Turkey, both starring Dick Van Dyke), Lear tried to sell a concept for a sitcom about a blue-collar American family to ABC-TV. They rejected the show after two pilots were filmed. After a third pilot was shot, CBS picked up the show, known as All in the Family. It premiered January 12, 1971 to disappointing ratings, but it took home several Emmy Awards that year, including Outstanding Comedy Series. The show did very well in summer reruns, and it flourished in the 1971-1972 season, becoming the top-rated show on TV for the next five years. After falling from the #1 spot, All in the Family still remained in the top ten, well after it transitioned into Archie Bunker's Place. The show was based on the British sitcom Til Death Us Do Part, about an irascible working-class Tory and his Socialist son-in-law.
Lear's second big TV hit was also based on a British sitcom, Steptoe and Son, about a west London junk dealer and his son. Lear changed the setting to the Watts section of Los Angeles and the characters to African-Americans, and the NBC-TV series Sanford and Son was an instant hit. Numerous hit shows followed thereafter, including Maude (the lead character of which was reportedly based on Lear's then-wife Frances), The Jeffersons (both spin-offs of All in the Family), One Day at a Time and Good Times.
What most of the Lear sitcoms had in common was that they were character-driven, had sets that more resembled stage plays than common sitcom sets, were shot on videotape in place of film, used a live studio audience, and most importantly dealt with the social and political issues of the day. Ironically, although Lear's shows are often considered somewhat autobiographical and closely identified with his personal experiences, his early hits were actually all adapted from someone else's creations: the two aforementioned British adaptations and Maude, while reputedly based on Lear's wife, was actually the brainchild of series producer Charlie Hauck. Bud Yorkin was also the major force behind All in the Family, Sanford and Son, The Jeffersons, and countless others.
Norman's longtime producing partner was Bud Yorkin, who created/produced All in the Family, Sanford and Son, What's Happening!!, Maude, and The Jeffersons, split with Lear in 1975. He started a production company with writer/producers Saul Turteltaub and Bernie Orenstein, but they had only two shows that ran more than a year: What's Happening!! and Carter Country. The Lear/Yorkin company was known as Tandem Productions. Lear and talent agent Jerry Perenchio founded T.A.T. Communications (T.A.T. stood for "Tuchus Affen Tisch", which is Yiddish for "Putting one's butt on the line") in 1974, which co-existed with Tandem Productions and was often referred to in periodicals as Tandem/T.A.T. The Lear organization was one of the most successful independent TV producers of the 1970s. TAT produced the influential and award-winning 1981 film The Wave about the Ron Jones' social experiment.
Lear also developed the cult favorite TV series Mary Hartman, Mary Hartman (MH MH) which was turned down by the networks as "too controversial" and placed it into first run syndication with 128 stations in January 1976. A year later, Lear added another program into first run syndication along with MH MH, All That Glitters. He planned in 1977 to offer three hours of prime time Saturday programming directly, with the stations placing his production company in the position of an occasional network.
Norman himself stepped down as production supervisor on his shows in 1978 to work on a film dealing with his concerns about the growing influence of radical right-wing evangelists. The film was never fully developed, but the process stimulated his long engagement in political activism.
In 1982, the company bought out Avco Embassy Pictures from Avco Financial Corporation, and the Avco part of its name was dropped. Embassy Pictures was led by Alan Horn and Martin Schaeffer, later co-founders of Castle Rock Entertainment with Rob Reiner. In 1985, Lear sold all his film and television production holdings to Columbia Pictures (then owned by the Coca-Cola Company) which acquired Embassy's film and television division (which included Embassy's in-house television productions and the television rights to the Embassy theatrical library) for $485 million in shares of The Coca-Cola Company. Lear and his longtime partner Jerry Perenchio split the net proceeds (about $250 mm). Coke later sold the film division to Dino De Laurentiis and the home video arm to Nelson entertainment (led by Barry Spikings).
The brand Tandem Productions was abandoned in 1986 with the cancellation of Diff'rent Strokes, and Embassy ceased to exist as a single entity in late 1987, having been split into different components owned by different entities. The Embassy TV division became ELP Communications in 1988, but shows originally produced by Embassy were now under the Columbia Pictures Television banner from 1988–1994 and the Columbia TriStar Television banner from 1994-1998.
Lear is unofficially credited with giving Rob Reiner, son of Carl Reiner (and a star of All in the Family) his start as a director by financing the mockumentary This is Spinal Tap. Lear's Act III Communications, founded in 1986 with Tom McGrath as President, produced several notable films, including Rob Reiner's next three films: The Sure Thing, Stand By Me, and The Princess Bride, as well as Fried Green Tomatoes.