She starred in the George White revue "Nice to See You" in 1953 at the Versailles Club, a dinner theatre. In September 1955, Stewart, a soprano, began a month-long engagement with "Kismet" at the Music circus in Lambertville, New Jersey. She has performed in over 35 musicals and plays on Broadway and in major Summer Stock productions around the country. She co-starred with Donald O'Connor in "Little Me", Gordon MacRae and Howard Keel in "Carousel", and Jack Carter in "Operation Mad Ball", "Born Yesterday" and "Critics Choice" from 1956 to 1957. She succeeded Jo Sullivan in "The Threepenny Opera", and was subsequently recruited by Frank Loesser to star in the revival of "The Most Happy Fella" in 1959.