Popov studied at the Moscow Circus School (1944–49) and then joined the circus as an eccentric tightrope walker. In 1952 he first appeared as a clown when the regular clown was injured. Using the film comedian Charlie Chaplin's tramp character as a model, Popov portrayed a gentle little man baffled by the big, precarious world; his act also incorporated his skills as an acrobat, juggler, and animal trainer. He first appeared abroad in 1955 at Warsaw, toured France, Belgium, and England in 1956, appeared in 1958 at the Brussels Exposition, in 1957 appeared on American television from Moscow, and in 1963 and 1972 toured the United States with the Moscow Circus.