Sean Ambrose is a former IMF agent who is the main antagonist of the 2000 film Mission: Impossible II.
He is portrayed by Dougray Scott.
Ambrose was presumbly born in the UK as stated by his nationality and he was an IMF agent who attempts to get his hands on a new deadly virus called Chimera, as well as its cure, Bellerophon. Ambrose has sold the virus for £37,000,000, and he intends to release the virus into the population and then sell the cure to the highest bidder. At the beginning, Ambrose was using an Ethan Hunt face mask while the latter was on holiday, steals the Chimera virus samples from Dr. Nekhorvich who had infected himself with a sample. Ethan Hunt is assigned a mission of recovering the virus with the help of three fellow agents (one of them being a British professional thief named Nyah Nordoff-Hall), and he manages to destroy a number of Chimera virus samples inside the biochemical firm Biocyte Pharmaceuticals' head office. Before Ethan can destroy the final sample, Ambrose appears and engages in a firefight with Ethan. He forces Nyah to get the virus for him, but she injects herself with it before he can stop her. Ambrose kidnaps Nyah and leaves, knowing that she is now valuable to him alive, but Ethan realizes that if he does not cure Nyah with Bellerophon within the next twenty hours and left unchecked, she will die along with a number of innocent people in Sydney.
Ethan's team later track Ambrose's men to the Biocyte storage bunker during a meeting and Ethan successfully steal the Bellerophon and Chimera samples from them. Meanwhile, Ethan's helicopter team locate Nyah on top of the cliff, who is about to commit suicide to prevent the Chimera virus inside her from spreading. Ethan and Ambrose have another firefight during a frantic motorcycle chase until the pair eventually fall onto a beach before engaging in hand-to-hand combat, with Ethan gaining the upper hand on Ambrose and knock him out. However, Ambrose is still alive and laughs triumphantly as he points Ethan's Beretta 92FS at his back. Ethan notices Ambrose's USP Compact half buried in the sand by his feet and kicks it into the air, grabs it and spins around after tossing a Bellerophon sample to his friend Luther Stickwell for him to cure Nyah. As Ambrose starts firing at him, Ethan drops to the ground before shooting Ambrose three times in the chest and back, killing him for good.