She was born Meredith Ann Baxter in South Pasadena, California, the daughter of actress and situation-comedy creator Whitney Blake and Tom Baxter, a radio announcer. She was raised in Southern California and has two brothers: Richard (born 1944) and Brian (born 1946). Her mother's widower was situation-comedy writer Allan Manings.

Baxter got her first big break on television in 1972 as one of the stars of the Bridget Loves Bernie, a CBS television-network situation comedy. The series was canceled after one season, but her co-star, David Birney became her second husband in 1974. Following their marriage and until their divorce in 1989, she was credited as Meredith Baxter-Birney.

As Baxter-Birney, she became widely known several years later on Family. She played the role of Nancy Lawrence Maitland and received two Emmy Award nominations for Outstanding Continuing Performance by a Supporting Actress in a Drama Series (1977 and 1978).

After Family ended, she starred with Annette O'Toole and Shelley Hack in Vanities (1981), a television production of the comedy-drama stage play about the lives, loves and friendship of three Texas cheerleaders starting from high school to post-college graduation; it aired as a part of Standing Room Only, a series on the premium-television channel HBO.

Baxter-Birney's next series was Family Ties, on which she played an ex-flower child mother, Elyse Keaton, on Family Ties. In reality, she is only fourteen years older than Michael J. Fox, who played her son Alex Keaton.

Following Family Ties, Baxter (whose marriage to Birney ended in 1989) produced and starred in television films. She portrayed a psychopathic kidnapper in The Kissing Place (1990) and was nominated for an Emmy Award for Outstanding Lead Actress in a Miniseries or a Special for her work in A Woman Scorned: The Betty Broderick Story (1992), based on the true story of a divorcée who was convicted of murder in the shooting of her ex-husband and his young wife.

In 1994, she won a Daytime Emmy Award for her role as a lesbian mother raising a young son, in Other Mothers (1993), a CBS Schoolbreak Special. For her work on the television film My Breast (1994), she received a special award for public awareness from the National Breast Cancer Coalition.

In 1997, Baxter once again played the mother of a character played by Fox, this time on Spin City, an ABC situation comedy.

In 2005, she began appearing in television commercials for Garden State Life Insurance Company. In 2006, she temporarily co-hosted — with Matt Lauer — Today, the NBC morning news and talk show. In 2007, she made a guest appearance on What About Brian, an ABC drama series. That same year, she also made several appearances as the dying mother of Detective Lilly Rush on Cold Case, a CBS police-procedural series. In 2009, she is guest starring in season two the web series We Have to Stop Now.

In recent years, Baxter has also created a skin-care line, Meredith Baxter Simple Works, which helps raise funds for her breast-cancer research foundation. She is also a spokesperson for Consumer Cellular, a cell phone company advertised as providing a cheaper cell phone alternative for senior citizens.