Jonah Blacksmith was formed by brothers Simon and Thomas Alstrup. The band name is a tribute to their grandfather Johannes Alstrup who was a blacksmith.

In addition to Simon Alstrup (vocals, guitar) and Thomas Alstrup (bass and banjo), Jonah Blacksmith consists of Lasse Alstrup (keys, mandolin), Jon Bisgaard Kjeldsen (keys, banjo), Søren Poulsen (drums), Thor Kortegaard (drums) and Søren Bigum (guitar, pedal-steel).