In the movie of the musical adaptation of the Dickens novel “Oliver Twist,” Mr. Wild sang the numbers “Consider Yourself” and “I’d Do Anything” as the charming, devilish Artful Dodger, one of underground crime lord Fagin’s thieving ragamuffins. He was nominated for an Oscar for his work. (David Jones, soon to become a member of the singing group The Monkees, played the part on Broadway.)

Mr. Wild’s success in the film led to the Sid and Marty Kroft children’s television series “H.R. Pufnstuf,” in which he played Jimmy, a boy living in a magical, vividly colored land peopled by large puppets and fantastical creatures. The series was very successful and spawned a 1970 film, “Pufnstuf,” in which he again played Jimmy. At this time, he also began a recording career.

Roles in the films “Melody,” “Flight of the Doves” and “The Pied Piper” followed, but Mr. Wild’s career was in decline by the mid-70s. He admitted to heavily drinking and smoking throughout the 1970s and ‘80s. He became sober in 1988. Nonetheless, these excesses led to his later being diagnosed with oral cancer. He underwent surgery, chemotherapy and radiotherapy. The cancer went into remission, but later returned, and he had his voice box and tongue removed. He was unable to speak, drink or eat during his last years and was fed through a tube that led into his stomach, the BBC reported.

He was working on his autobiography at the time of his death.

Jack Wild was born in Royton, England, on Sept. 30, 1952. He was discovered by talent agent June Collins, the mother of rock star Phil Collins. He is survived by his Clare Harding.