Wes Ramsey (4 episodes, 2003-2006), Season 6 (2 episodes), 7 (1 episode), 8 (1 episode)
Jason Simmons (43 episodes, 2003-2006) Season 5-8
Kristopher Simmons (43 episode, 2003-2006), Season 5-8

In Season 5 Wyatt was also portrayed by several babies, whose names are not known. From Season 6 on the young Wyatt was only played by Jason and Kristopher Simmons.