Prior to Lorimar, Rich had an established reputation first as an advertising executive at Benton & Bowles, then as a television producer, co-producing (with Walter Mirisch) successful series such as The Rat Patrol.

The Homecoming: A Christmas Story, airing during the 1971 holiday season, was a ratings success, and served as the pilot for Lorimar's first major hit, The Waltons, which premiered in 1972.

[4] In the 1984–85 season, three of the top 10 shows in the United States were produced by Lorimar; Dallas, Knots Landing, and Falcon Crest.

In the mid-1980s, Lorimar's output swung toward family-friendly sitcoms; among these were The Hogan Family (initially titled Valerie), Perfect Strangers, and Full House, which were produced by Miller-Boyett Productions.

On February 19, 1986, the Lorimar-Telepictures merger was completed and the company started trading on the New York Stock Exchange as "LT".

[20] In 1991, after Orion Pictures shut down its television unit, Gary Nardino moved to Lorimar, taking some Orion-produced shows and talent deals (Thomas Carter, Robert Townsend, Paul Stojanovich, Clifton Campbell and Deborah Joy LeVine) with them.

[22] Lorimar continued as a production company until September 1993, when it was eventually consolidated into Warner Bros. Television, primarily for economic reasons.

Several shows slated to be Lorimar productions, such as Lois & Clark: The New Adventures of Superman, Living Single, It Had to Be You, Café Americain, The Trouble with Larry and Family Album ended up being produced by Warner Bros.[24] Les Moonves, who would later become the chairman and CEO of CBS Corporation, was the president and CEO of Lorimar Television from 1990 to 1993.

By late 1984, the entire unit began to ramp up operations, including a deal with Sidney Lumet to develop feature films.

[29][30] That year, New Century/Vista Film Co., a joint venture of The Vista Organization and New Century Entertainment, struck a deal with Lorimar for international distribution.

[31] Several Vista productions were distributed by Lorimar, including Rented Lips, Pass the Ammo and Fright Night Part II.

[32] Lorimar also acquired international theatrical and other ancillary rights to Return of the Living Dead Part II.

[41] Other areas of growth included Karl-Lorimar's distribution of the Shades of Love direct-to-video romance series (in cooperation with Canada's Astral Film Enterprises)[42] and Jazzvisions, featuring jazz concerts from Herbie Hancock, Antonio Carlos Jobim, John Scofield, George Duke, Tito Puente and Etta James, as well as a big-band jazz production of Porgy and Bess.

[43] By early 1987, while the company's expansion (including a deal with international film distributor Cinecom Entertainment Group)[44] continued, the relationship between Lorimar and Karl had turned sour, primarily thanks to the division racking up financial losses from failed experiments; as a result, Karl resigned in March 1987 due to violating the company's ethical guidelines.