Theatre in London, Ken Attiwill and Evadne Price's play Once a Crook as Hallelujah Harry from 3 June 1940 to 12 July 1941, and Patrick Hamilton's play The Duke in Darkness from 1942 to 1943 at the Bristol Hippodrome. Postwar Following the end of the Second World War on 4 September 1945, Johns continued to be cast in leading roles. In Robert Hamer's 1945 crime drama film Pink String and Sealing Wax, he played the "unexpectedly severe" Mr. Edward Sutton, a middle-class Victorian and newly appointed court analyst; in Norman Walker's 1946 drama film They Knew Mr. Knight, he played the main protagonist Tom Blake, playing to his "fretful features"; in Paul L. Stein's 1948 thriller film Counterblast, he played Doctor Bruckner the Beast of Ravensbruck, an escaped Nazi who murders a visiting scientist from Australia and assumes his identity, "in splendid villainous mode". His supporting roles in this era included playing Ernest Bennett in Ralph Thomas' romantic comedy film Helter Skelter, and Bob Cratchit in Brian Desmond Hurst's 1951 Christmas fantasy drama film adaptation of Charles Dickens's A Christmas Carol, with Alastair Sim as the cantankerous title character and miser. On stage, he appeared in Erskine Caldwell and Jack Kirkland's production of Tobacco Road at the West End in 1949, Michael Norbury's play Love’s a Funny Thing from 10 to 12 March 1949 at The Ambassadors Theatre in London, Harold Martin's play The Martins’ Nest from 12 April to 12 May 1951 at the Westminster Theatre in London, James Forsyth's play Fulbert as the uncle and guardian of Heloise beginning on 14 November 1951 at the Duke of York's Theatre in London, and Eric Linklater's play The Mortimer Touch as Shurie from 30 April to 7 June 1952 at the same theatre. Though he had appeared in several television films, Johns made his television series debut relatively late when he was cast as Harold Simpson in the episode The Happy Sunday Afternoon of BBC Sunday Night Theatre in 1950. On the same show, he was given the role of Albert Eccles in the 1954 episode Caste, Samuel Pepys in the 1954 episode Ninety Sail, Rough in the 1957 episode Gaslight, and His Excellency the Governor in the 1957 episode His Excellency. In 1956, Johns was given the lead role of J. Philimore Sparkes in six episodes of the television series New Ramps For Old, in which he was cast