Tewes was born in Braddock, Pennsylvania, of German extraction and one of 4 children, to Joanne and Joseph Robert Tewes, a wood pattern maker. Her early childhood was spent in industrial Trafford, near Pittsburgh before the family moved to Whittier, California, when she was 8. Tewes attended Ada S. Nelson Elementary School and Pioneer High School, where she studied Drama, winning Best Actress award for 3 years. Tewes enrolled on an associate of arts degree at Rio Hondo College, deciding to major in Theatre Arts. At college, she won "The Chancellor's Award for Excellence in Theatre", a one-year scholarship which enabled her to transfer to the University of California, Riverside, as a sophomore. In 1973, when her scholarship expired, Tewes withdrew from university and joined the Pacific Conservatory Theatre in Santa Maria, California, as an apprentice, making her stage debut in Arsenic and Old Lace and The Most Happy Fella before becoming a member of the Birdcage Theatre Company at Knott's Berry Farm, an amusement complex outside Los Angeles.
Career
Tewe's first break came in mid-1974 when she starred in a Lipton Ice Tea commercial, allowing her to join the Screen Actors Guild and register with an agent with the prospect to work on film projects. In 1975, whilst waitressing in Sunset Boulevard coffee shops and penniless, she suffered a traumatic loss when her mother was diagnosed with terminal cancer and died a year later. Tewes obtained minor parts in the TV series Charlie's Angels and Family as Jill Redfield, a disenchanted Pasadena debutante. However, it was her role in Starsky and Hutch as Sharon Freemont, an assistant attorney which brought her to the attention of Aaron Spelling. Tewes was cast for the role of cruise director Julie McCoy on The Love Boat, selected from more than 100 actresses who auditioned. She starred in the third and final pilot of the show, cast the day before production began on the RMS Queen Mary in San Pedro. Tewes recalls the pilot episode: "I had to borrow money to get a new tire, because my ’62 Volkswagen Bug was not going to get to San Pedro…. That first day, standing there in the little outfit, and I had to say, ”Hi, welcome aboard, I’m Julie McCoy, your cruise director” a gazillion times. But I kept screwing it up and saying, ”Hi, welcome aboard, I’m Julie MacLeod…” because I was talking to Gavin MacLeod and I was so excited." In parallel, Tewes appeared in 1979 TV film Dallas Cowboys Cheerleaders alongside Jane Seymour and made her film debut in the 1981 movie Eyes of a Stranger, which co-starred a young Jennifer Jason Leigh. In 1984, after seven seasons, Tewes was replaced on The Love Boat after a highly public battle with cocaine addiction which began recreationally in 1977 but which she eventually overcame. She did reprise her role as a guest in a 1985 episode, and in the TV movies in the 1986-87 season. Tewes was cast in a 1985 CBS sitcom pilot Anything for Love. The pilot aired as a special that summer, but was not picked up as a series. She went on to star in classic 1980s TV series The New Mike Hammer, Murder, She Wrote, T.J. Hooker and Hunter. In 1994, Tewes moved to Seattle and focused on regional theatre acting and directing across the country. In Seattle, she performed with the Tacoma Actors Guild and the Seattle Repertory Theatre. As well as doing voice-overs for commercials, Tewes continued her TV career and appeared in a 1998 episode of , a revival of the original series. In 2000–01, she had a recurring role as a police detective on The Fugitive. Tewes plays Maxine Murdoch in the Imagination Theatre comedy-mystery radio series Murder and the Murdochs, which debuted in 2020. She has also played roles in episodes of other radio series on Imagination Theatre.
Tewes has been married three times, first to John Wassel, a TV commercials director, then to Paolo Nonnis, an Italian drummer, and finally stage actor Robert Nadir. In 1987, she suffered the loss of her one month-old daughter, born premature.
