Yasbeck was born in the Cincinnati suburb of Blue Ash, Ohio, the daughter of Dorothy Louise Mary (née Murphy; 1922–1984), a homemaker, and John Anthony Yasbeck (1921–1982), a butcher and grocery store owner. Her father was of Lebanese descent, while her mother was of Irish ancestry. As a child, Yasbeck was featured on the package art for the Betty Crocker Easy-Bake Oven. Years later, in 2000, she was presented with a new Easy-Bake Oven on the show I've Got a Secret, for which she was a regular panel member.
She spent her primary and secondary years at two different Catholic schools: Summit Country Day School and Ursuline Academy. After losing both of her parents, her father from a heart attack and her mother from emphysema, Yasbeck moved to New York City.
Early into her acting career, she appeared in Rockhopper, an unsold CBS television pilot from 1985. Yasbeck has had guest-starring roles in many television shows, including Dallas, Spies, Werewolf, J.J. Starbuck, Magnum, P.I., China Beach, and Murphy Brown. She played Olivia Reed for four months between 1986 and 1987 on the long-running daytime soap opera Days of Our Lives. She also played the starring role of the mermaid Madison in the Disney television movie Splash, Too in 1988 (the role of Madison was originated by Daryl Hannah in the 1984 movie Splash). Playing a mermaid in Splash, Too was a fulfillment of a childhood dream for Yasbeck, as she loved mermaids when she was 5 years old after watching a Disney movie that featured mermaids. Yasbeck has also had starring roles in the sitcoms Wings, Alright Already, and Life on a Stick and in movies such as House II: The Second Story, Pretty Woman, Problem Child, Problem Child 2, and The Mask. She has twice worked with Mel Brooks, in 1993's Robin Hood: Men in Tights and 1995's Dracula: Dead and Loving It.
Yasbeck also appeared once on the hit DCOS That's So Raven as the mother of one of the main characters, Chelsea. The episode originally aired on September 22, 2006.
In late 2007, plans surfaced of a potential That's So Raven spin-off featuring Yasbeck and Anneliese van der Pol, who portrayed her daughter, with occasional appearances by Raven-Symoné. The show was scrapped due to van der Pol signing onto a new Broadway play, and Yasbeck wanting to take a break from acting to focus on her family.
She was a contestant on Are You Smarter Than a 5th Grader? in 2010.
Yasbeck is the widow of actor John Ritter, with whom she had worked in several projects. She first met him at director Dennis Dugan's house during a read-through of their 1990 movie Problem Child. According to Yasbeck, Ritter forced her to eat a bagel and cream cheese because he thought she was too thin. He also thought she was too young to play his wife in the movie (Ritter was 14 years Yasbeck's senior).
Yasbeck and Ritter also starred together in Problem Child 2 (1991) and guest-starred together in an episode of The Cosby Show which aired in 1991. Ritter also guest-starred on Wings as Yasbeck's estranged husband in the season-seven episode "Love Overboard". The couple had a daughter, Stella Dorothy, in September 1998, and married one year later on September 18, 1999 at the Murphy Theatre in Wilmington, Ohio.
On September 11, 2003, their daughter Stella's birthday, Ritter fell into a coma when rehearsing for 8 Simple Rules for Dating My Teenage Daughter. He was taken to the hospital by paramedics. He drifted in and out of consciousness and told his feelings to doctors. Initially, Ritter was thought to be suffering a heart attack. At 10:48 that night, Ritter died. The cause of death was actually an aortic dissection stemming from a previously undiagnosed congenital heart defect.
Yasbeck gave her blessing to the continuation of the sitcom, as 8 Simple Rules, where it was ultimately decided that Katey Sagal's character would assume the lead role as a widow.
Yasbeck appeared on Larry King Live on June 16, 2008, to discuss heart disease in the wake of television personality Tim Russert's death.
On the September 5, 1990, episode of The Tonight Show Starring Johnny Carson, she said that her "great-great-great uncle" Charles Webb Murphy was the owner of the Chicago Cubs during their championships of the early 1900s.
After her husband died, Yasbeck filed a $67 million wrongful death lawsuit against Providence Saint Joseph Medical Center and several doctors who treated him, alleging they misdiagnosed his condition and that contributed to his death. Several of the defendants settled out of court for a total of $14 million, including Providence St. Joseph, which settled for $9.4 million. On March 14, 2008, a jury split 9–3 in favor of the doctors, clearing the physicians of any wrongdoing.Yasbeck, Amy (2010). With Love and Laughter, John Ritter. ISBN 978-1-4165-9841-1.