| Year | Award | Category | Work | Result | Ref. |
| 2011 | SFX Awards | Best Sci-Fi or Fantasy Actor | Being Human | Nominated | |
| Sexiest Male | Nominated | |
| 2012 | Online Film & Television Association | Best Original Song (Shared with cast) | The Hobbit: An Unexpected Journey | Nominated | |
| SFX Awards | Best Sci-Fi Actor | Being Human | Nominated | |
| Sexiest Male | Nominated | |
| 2013 | The Hobbit: An Unexpected Journey | Nominated | |
| 2014 | Empire Awards | Best Male Newcomer | Won | |
| CinEuphoria Awards | Best Ensemble | Nominated | |
| 2015 | Radio Times Champion | Drama Champion | Poldark | Won | |
| TV Choice Awards | Best Actor | Nominated | |
| 2016 | Broadcasting Press Guild Awards | Breakthrough Award | Poldark / And Then There Were None | Won | |
| Best Actor | Nominated | |
| GQ Men of the Year | Best TV Actor | Poldark | Won | |
| Irish Film and Television Awards | Best Actor in Lead Role | Nominated | |
| Monte-Carlo Television Festival | Outstanding Actor in a TV Series-Drama | Nominated | |
| National Television Awards | Impact Award | Won | |
| Drama Performance | Nominated | |
| Radio Times Champion | Drama Champion | Won | |
| 2017 | Irish Film and Television Awards | Best Actor in Lead Role | Nominated | |
| TV Times Awards | Favourite Actor | Nominated | |
| TV Choice Awards | Best Actor | Nominated | |
| 2018 | Nominated | |
| Stage Debut Awards | Joe Allen Best West End Debut Award | The Lieutenant of Inishmore | Won | |
| 2019 | TV Choice Awards | Best Actor | Poldark | Nominated | |
| 2023 | Irish Film and Television Awards | Best Actor inn a Lead Role - Drama | The Suspect | Nominated | |
| Sichuan TV Festival | Best Actor in a Leading Role for a Television Series | Leonardo | Nominated | |