 Walker was doing concert work and had returned from a production of "The Gondoliers" in Limerick, Ireland, in 1949, when D'Oyly Carte asked him to step in as an emergency replacement, initially filling in as Grosvenor in "Patience" (Prestige wrote that his "interpretation ... can only be described as magnificent") and then Bouncer, Counsel, Bobstay, Pish-Tush, the Lieutenant, and Giuseppe in "The Gondoliers" for the remainder of the season.His total of 35 Savoy Opera roles while a member of the D'Oyly Carte Opera Company is the company's all-time record.After his last season with D'Oyly Carte, Walker and Roberts were engaged by the J. C. Williamson Gilbert and Sullivan Opera Company, and toured Australia and New Zealand throughout the 1950s and early 1960s.