Fairchild moved to Los Angeles and was cast as Jenna Wade in the television series Dallas in 1978, appearing in one episode (the role was later played by Priscilla Presley). Penthouse magazine had an article on Fairchild in the '70s in which her interest and prowess in martial arts was featured; the article stated "Watch out for Morgan Fairchild, she'll rip your face off." In the late-1970s, she had a stint on Mork & Mindy and then achieved success as the resident vixen, Constance Weldon Carlyle, on the primetime soap opera Flamingo Road. Though the series had an impressive beginning, the ratings soon went down and it was canceled after two seasons. Fairchild was nominated for a Golden Globe. She then starred in The Concrete Cowboys, a 1979 TV movie. In 1982, she played Jamie Douglas, a newscaster, in the sexy thriller The Seduction, and in 1984 she starred in Paper Dolls, where critics considered her the only bright spot, but poor ratings doomed the series. By this time she was established as a leading television actress and appeared in the series Falcon Crest, playing a season long character named Jordan Roberts, her name appeared in the closing credits through the series' fifth season (1985-1986). In the early 1980s she appeared in off-Broadway plays such as Geniuses and garnered rave reviews from Time magazine and The New York Times.

Tommy Flanagan, Jon Lovitz's popular recurring character on Saturday Night Live in the mid-1980s, was a pathological liar (catchphrase: "Yeah, that's the ticket") who often claimed to be married to Fairchild ("....with my wife, Morgan Fairchild, whom I've seen naked.") Fairchild garnered an Emmy Award nomination for her role in a Murphy Brown episode and in the early 1990s Roseanne producers cast her in a role as Sandra Bernhard's bisexual girlfriend.

In 1995, Fairchild returned to soaps as catty Sydney Chase on The City, for a year. She also made guest appearances on Friends (as Chandler Bing's mother, Nora) and was a recurring guest star on Cybill as Andrea, the rival of Cybill Shepherd's character. Through the years, she also maintained a career in independent films and theater productions. More recently, Fairchild has starred in the role of Mrs. Robinson in the play adaptation of the film The Graduate. This role drew media attention, as it includes a scene in which Fairchild appeared nude on stage. In 2005, Fairchild appeared in the competition reality show, But Can They Sing? on the VH1 network. In 2006, she was a charter cast member of the My Network TV series Fashion House, playing Sophia Blakely, a rival to Bo Derek's character, Maria Gianni. In addition to her work as an actress Fairchild has long maintained a strong role within the Screen Actors Guild. Currently Fairchild is a three year board member of the Guild and has served on several diverse committees, including co-chair Legislative Committee, National Executive Committee, SAG-AFTRA Relations Committee, Commercials Contracts Committee, Honors and Tributes Committee (HATS), and Guild Governance and Rules Committee. In recognition of her political work Esquire magazine said of Fairchild: "She looks like a centerfold but sounds like a senator".

• Code Enforcer (2009) (filming) .... Mrs. Brown
• Spring Break '83 (2009) (post-production) .... Mouth's Mother
• "Chuck" .... Honey (1 episode, 2008)
       - Chuck Versus the Sensei (2008) TV episode .... Honey
• The Sno Cone Stand Inc (2008) .... Cathy Wanton
• The Steamroom (2008) .... Sheila
• "Two and a Half Men" .... Donna (1 episode, 2007)
       - Young People Have Phlegm Too (2007) TV episode .... Donna
• "Fashion House" .... Sophia Blakely (36 episodes, 2006)
       - A New Foundation (2006) TV episode .... Sophia Blakely
       - Falling Apart at the Seams (2006) TV episode .... Sophia Blakely
       - Maria's Final Bow (2006) TV episode .... Sophia Blakely
       - Breaking Point (2006) TV episode .... Sophia Blakely
       - The Betrayal (2006) TV episode .... Sophia Blakely
        (31 more)
• The Initiation of Sarah (2006) (TV) .... Trina Goodwin
• Shock to the System (2006) .... Phyllis Hale
• "That '70s Show" .... Carolyn (1 episode, 2004)
       - Going Mobile (2004) TV episode .... Carolyn
• Knuckle Sandwich (2004) .... Mrs. Simms
• "Just Shoot Me!" .... Lily Barton (1 episode, 2003)
       - Pictures of Lily (2003) TV episode .... Lily Barton
• Arizona Summer (2003) .... Debbie
• I Was a Teenage Faust (2002) (TV) .... Babylonia