Her comedic scenes with Ginger Rogers in The Major and the Minor were well received, and in 1944 she scored an outstanding success in Preston Sturges' The Miracle of Morgan's Creek. She appeared in two Henry Aldrich films, and played Writer Emily Kimbrough in two films Our Hearts Were Young and Gay and Our Hearts Were Growing Up both co-starring Gail Russell.
In 1947, a three-record album of Lynn's piano playing included Mozart's Rondo, Laura, and Body and Soul.
Lynn married Architect John C. Lindsay December 18, 1948; they divorced in June 1953. Lynn was then married in 1956 to Mortimer Hall, son of New York Post newspaper publisher Dorothy Schiff.
During the 1950s, Lynn acted in a number of films, portraying Spencer Tracy's daughter in the crime drama The People Against O'Hara and the female lead in the much lampooned Bedtime for Bonzo opposite Ronald Reagan. She also had many TV leading roles during the 1950s, particularly in the middle years of the decade. As a solo Pianist, she released at least one single on Capitol Records with backing by the Paul Weston orchestra.
She acted frequently in television guest roles throughout the 1960s. By 1970, she had virtually retired from acting and had relocated to New York City, where she was running a travel agency. She appeared in Company of Killers, a film made for television. Paramount then offered her a part in a new film, Play It as It Lays, and after some consideration, Lynn accepted the offer and moved back to Los Angeles.
In 1964, Lynn had a six-month stint on Broadway, replacing Barbara Bel Geddes in Mary, Mary. In the early 1950s, she starred with Maurice Evans in The Wild Duck on Broadway.
Before filming started on Play It as It Lays, Lynn suffered a stroke and died on December 18, 1971, at the age of 45. Lynn was cremated. A funeral Service was held at Church of the Heavenly Rest in New York City, and a memorial Service was held at All Saints Episcopal Church in Beverly Hills, California.
Another daughter, Susan, a.k.a. Daisy Hall, is an alumna of the Emma Willard School for Girls in Troy, New York, and as an Actress herself, has starred in numerous French- and lesser-known American-produced films, during the 1980s, '90s and 2000s.