Donovan grew up in Maryhill, Glasgow, Scotland. He contracted polio as a child when he was vaccinated (this was in the period before the introduction of the safer Sabin oral vaccine), and the disease and subsequent treatment left him with a limp.
In mid-1966, Donovan became the first high-profile British pop star to be arrested for possession of marijuana. Donovan's drug use appears to have been moderate, and was mostly restricted to pot smoking — with occasional use of LSD and mescaline, although he was not indulging on the herculean scale of friends like John Lennon and Brian Jones; his use of LSD is referred to in many of his lyrics, including "The Trip", "Sunshine Superman", "Wear Your Love Like Heaven", "Epistle To Dippy", and "Hurdy-Gurdy Man".
In 2005, his autobiography The Hurdy Gurdy Man was published.