Hugh Michael Horace Dancy was born in Stoke-on-Trent, Staffordshire, England, to Sarah Ann (Birley), who works in academic publishing, and Jonathan Peter Dancy, a philosophy professor and writer. He has a brother, Jack, and a sister, Kate. He was raised in Newcastle-under-Lyme.
Dancy married American actress Claire Danes in 2009. The couple has one child.