Willie Loomis is a character on the ABC-TV cult television Gothic Horror Soap Opera serial Dark Shadows. The character was first played by James Hall and later by John Karlen. He was a drifter, and a friend of Jason McGuire (Dennis Patrick ). While both of them stayed at Collinwood , Jason blackmailed Elizabeth Collins Stoddard (Joan Bennett).

In 1967, Willie Loomis was snooping about for jewels or something of equal value at Eagle Hill Cementary in Collinsport, Maine . His foraging led him to the family mausoleum of a wealthy and extinct, he assumed rich old family (The Collinses). There, the inquistive and larcenous Willie found and opened a coffin sealed with locks and chains. In so doing he released a vampire named Barnabas Collins (Jonathan Frid). Barnabas enthralled Willie, making him his slave and servant. That same year Maggie Evans was kidnapped, and utilised as bait in a trap for Barnabas set by Sheriff George Patterson (originally played by Dana Elcar) and Doctor Dave Woodward played by Robert Gerringer . Inadvertently, Willie was caught in it, shot and wounded seriously. He was taken to the Collinsport Hospital in a comatose state and would later be diagnosed insane. He was transferred to Wyndcliffe Sanitarium, from which he was released in 1968.