2013–present: Peaky Blinders and Oppenheimer
Beginning in 2013, Murphy starred as Thomas Shelby in the BBC television series Peaky Blinders, a series about a criminal gang in Birmingham during the post-World War I period. Jason Statham was initially picked for the role by director Steven Knight, who met both actors to talk about the role. Knight later said, "Cillian, when you meet him, isn't Tommy, obviously, but I was stupid enough not to understand that". He picked Murphy after receiving a text message from Murphy that read, "Remember, I'm an actor". Murphy told The Independent, "[The scripts] were so compelling and confident, and the character was so rich and complex, layered and contradictory. I was like, 'I have to do this.'" Peaky Blinders was praised and received high ratings. A second series began broadcasting on the BBC in October 2014. On 25 August 2019, the first episode of season 5 was broadcast on BBC One. In an interview with Digital Spy, director Anthony Byrne said, "if we did start shooting in January (2021), we wouldn't finish until May or June and then it's another 6 months of editing". Series six premiered on 27 February 2022.
In 2013, Murphy made his directorial debut with a music video for the band Money's single Hold Me Forever. The video features dancers from the English National Ballet and was filmed at The Old Vic Theatre in London. In 2014, Murphy starred in the drama Aloft, and Wally Pfister's Transcendence. Both of these garnered mostly unfavourable critic reviews according to the aggregator Rotten Tomatoes. That same year, Murphy reunited with Enda Walsh in the play Ballyturk. He starred in Ron Howard's 2015 film In the Heart of the Sea. In 2015, he contributed spoken vocals to the tracks "8:58" and "The Clock" from Paul Hartnoll's album 8:58. The two previously met while Hartnoll was scoring the second season of Peaky Blinders. In 2016, Murphy starred in Ben Wheatley's Free Fire, and appeared in Anthropoid, in which he portrayed Czechoslovak World War II army soldier Jozef Gabčík, who was involved in Operation Anthropoid, the assassination of Reinhard Heydrich. Rupert Hawksley of The Telegraph said that Murphy's performance in Anthropoid was "solid, if unremarkable" and that he was "not asked to do an awful lot, other than smoke and look perplexed".
In 2017, Murphy played a shell-shocked army officer who is recovered from a wrecked ship in Christopher Nolan's war film Dunkirk, which emerged as a critical and box-office success. He felt that his character, who is nameless and was credited simply as Shivering Soldier, was "representative of something experienced by thousands of soldiers, which is the profound emotional and psychological toll that war can have". Murphy has also played a role in the feature film Anna as Miller, released in June 2019. His next release, A Quiet Place Part II (2021), stars Murphy as Emmett, a hardened survivor and old family friend of the Abbotts. Murphy's character reluctantly takes in the Abbotts following the events of the first film. Peter Bradshaw of The Guardian praised his performance.
Since 2020, Murphy has hosted Cillian Murphy's Limited Edition, a limited-run radio series broadcasting on BBC Radio 6 Music in which he draws from his personal music collection and answers "reasonable questions" from listeners. As of 2024, three seasons of Limited Edition have been produced, totalling 28 episodes.
Murphy portrayed J. Robert Oppenheimer in the biographical thriller Oppenheimer, released in 2023. The film marks the sixth collaboration between Nolan and Murphy, and the first starring Murphy as the lead. To prepare for the role, Murphy lost a significant amount of weight to match Oppenheimer's near-emaciated appearance, extensively researched Oppenheimer's life and took inspiration from David Bowie's appearance in the 1970s. Murphy's performance was lauded, with Empire's Dan Jolin writing: "At the film's pulsing nucleus is Murphy as Oppenheimer, and he is compelling throughout." For his performance, he won the Golden Globe Award for Best Actor in a Motion Picture – Drama, the BAFTA Award for Best Actor in a Leading Role, the Actor Award for Outstanding Performance by a Male Actor in a Leading Role, and the Academy Award for Best Actor. He was the first Irish-born performer to win the Academy Award for Best Actor.
Murphy launched the independent production company Big Things Films with Alan Moloney in February 2024. He produced and starred in the historical drama Small Things like These, which opened the 74th Berlin International Film Festival, and the drama film Steve, through a collaboration with Netflix. Murphy executive produced two of the sequels to 28 Days Later, titled 28 Years Later and 28 Years Later: The Bone Temple, reprising his role as Jim in the latter. In 2026, Murphy reprised his role as Shelby in the film Peaky Blinders: The Immortal Man, which served as a continuation of the Peaky Blinders series.