Final answer:
Daniel Day-Lewis retired from acting after his role in the film Phantom Thread, where he was nominated for an Oscar for Best Actor.
Step-by-step explanation:
The actor who announced his retirement after his role in Phantom Thread is Daniel Day-Lewis. Known for his meticulous method acting and dedication to his roles, Day-Lewis's performance in Phantom Thread was highly acclaimed, and he earned an Oscar nomination for Best Actor for his portrayal of the obsessive fashion designer, Reynolds Woodcock. It was after this film that Day-Lewis announced he would be retiring from acting, a decision that shocked fans and the film industry.