In 1960 Junkin joined Joan Littlewood's Stratford East Theatre Workshop and played the lead in the original production of Sparrers Can't Sing. A few years later he joined the Royal Court Theatre company and was the foil to Tony Hancock in some of Hancock's last work for British television. He played a diverse range of roles on the small screen; however, he is best remembered for his comedy roles and his appearances as a television quiz master. Worldwide filmgoers will remember him best for playing "Shake", the assistant to Norman Rossington, in the Beatles film A Hard Day's Night. In comedy roles, Junkin was rarely short of work, on account of his outstanding ability to play the stony-faced symbol of low level, petty-minded and unquestioning authority, whether the army sergeant, police constable or site foreman.