[1] In his early career, MacNeill appeared in such films as Fifty Dead Men Walking[2] and Peacefire directed by Macdara Vallely.
[3] He also played the character of Dave in Five Minutes of Heaven,[4] which was directed by Oliver Hirschbiegel and premiered at the 2009 Sundance Film Festival.
[11] In 2016, MacNeill appeared in Whit Stillman's film Love & Friendship[12] and in the final episodes of the RTE/BBC series The Fall.
[16] He reprised his role as Diarmuid Corcoran in the Broadway transfer of the show at Bernard B. Jacobs Theatre in late 2018.
[20] MacNeill appears in the thriller film Bring Them Down, due to be released in Irish and UK cinemas on 7 February 2025.