John MacCarthy, known on set as Johnny Mac, is the first assistant director. He works on the "even"-numbered episodes of Supernatural, while Kevin Parks works on the odd-numbered ones. He also worked with Jensen on Dark Angel.
MacCarthy's father passed away while he was directing 10.06 Ask Jeeves and he was honoured with an "In Memory" title card at the end of the episode.
- 7.20 The Girl with the Dungeons and Dragons Tattoo
- 9.08 Rock and a Hard Place
- 10.06 Ask Jeeves
- 12.14 The Raid