They had a son and two daughters. Later in 1950 Quilley joined the Old Vic Company for a British Council tour of Italy, playing Fabian in Twelfth Night and Gratiano in The Merchant of Venice. He took part in a revival of the 17th century gigue Michael and Francis at Hampton Court as part of the Festival of Britain in 1951, and sang in other performances by the London Opera Club alongside established opera singers, including their fifth anniversary concert at the Arts Council in 1953. In 1953 he appeared in revue, with Max Adrian, Betty Marsden and Moyra Fraser in Airs on a Shoestring, which ran for more than 700 performances. In 1955 he had his first leading role in a West End production, playing Geoffrey Morris in the musical Wild Thyme, by Philip Guard and Donald Swann. In The Manchester Guardian, Philip Hope-Wallace wrote, "Denis Quilley turns out a comparatively rare figure nowadays: a presentable singing English hero, a most likeable performance." In 1956 Quilley opened in another long-running show, Grab Me a Gondola which played for more than 600 performances. One of Quilley's other singing roles of the 1950s was the title character in Leonard Bernstein's operetta Candide. It ran for only sixty performances in this first London production in 1959; Quilley returned to the piece later in his career, playing the bombastic Baron and the misanthropic Martin in a National Theatre production in 1999. Quilley made no cinema films in the 1950s, but appeared in several television productions, ranging from Shakespeare (Bassanio in The Merchant of Venice, 1955) to detective fiction (John Wilton in Dancers in Mourning (1959). 1960s After playing in short runs of non-musical productions Quilley returned to a singing role in 1960, when he took over from Keith Michell as Nestor-le-Fripe in Irma la Douce. He made his first Broadway appearance the following year, again taking over the part of Nestor and subsequently touring the US with the production. After returning to England, he appeared at the Open Air Theatre, Regent's Park in June, 1963, as Benedick in Much Ado About Nothing. In November of that year he played Antipholus of Ephesus in The Boys From Syracuse, with Bob Monkhouse as his twin brother, also recorded. At the Savoy in 1964 he played Charles Condomine in the musical High Spirits, an adaptation of Coward's Blithe Spirit which had a run of three months.