Matthew McConaughey — The McConaissance

For a decade, McConaughey was Hollywood's shirtless rom-com guy: How to Lose a Guy in 10 Days, Failure to Launch, Fool's Gold. Then in 2011, he stopped taking those roles entirely. The result: Mud (2012), Dallas Buyers Club (2013, Best Actor Oscar — he lost 47 pounds for the role), True Detective Season 1 (the greatest single-season TV performance in the 2010s), and Interstellar. The "McConaissance" is the gold standard for celebrity reinvention because he didn't just get better — he actively destroyed his old brand to build a new one. That takes terrifying conviction.