But delve into his work and you'll soon discover how eagerly he embraces pop music in its purest, most accessible forms.
The outsider moniker will always stick, mind. Johnston's battles with bipolar mental illness, which culminated in years of institutionalisation through the 1990s, colour his fantastic drawings and sheath his music in an eggshell veneer.
His naive, lo-fi cassette-only releases of the early '80s document obsessions with good and evil, romance and rejection, comic-book characters and the Fab Four.
But, over time, the golden seam that runs through Johnston's output attracted attention from other artists, mainstream and fringe, elevating his profile and encouraging him in his work. The 2006 documentary The Devil And Daniel Johnston spread his fame still wider.
Today, it's hip to be a Johnston acolyte. Earlier this year, he featured at Auckland's Laneway Festival. His songs have been covered by the likes of Beck, Eels, Sparklehorse, Yo La Tengo, Tom Waits and, most recently, Karen O.
Kurt Cobain once wore a Johnston-designed T-shirt and listed Yip! Jump Music at No35 on his list of 50 favourite albums.
The 1983 release is a charming and melody-rich distillation of the then 22-year-old artist's compulsions. Recorded on a boom box in his brother's garage in Houston, Texas, the 20 songs are propelled along by a toy chord organ, which Johnston thumps percussively, and ukulele.
Johnston's child-like vocals are tunefully sweet as he sings of rocket ships, King Kong, Casper the friendly ghost, long-time inspiration the Beatles and love.
Sorry Entertainer, Danny Don't Rapp and Worried Shoes are Johnston classics, heart-warming and heartbreaking in the same breath, while Don't Let The Sun Go Down On Your Grievances is as flawless a gospel song as any you could name. By record's end, the outsider has found his way in.
