What character did Sean Penn play in his Oscar-winning supporting role?

Sean Penn played Col. Steven J. Lockjaw in his Oscar-winning supporting role.

Penn won Best Supporting Actor at the 98th Academy Awards for playing Col. Steven J. Lockjaw in One Battle After Another. The character is part of Paul Thomas Anderson’s politically charged action thriller, which follows a former revolutionary whose past conflict returns to threaten his family.

The role marked Penn’s third competitive acting Oscar. He had previously won Best Actor for Mystic River in 2004 and Milk in 2009. This victory came in the supporting category, where he competed against fellow One Battle After Another actor Benicio del Toro, along with Jacob Elordi, Delroy Lindo, and Stellan Skarsgård.

The film itself was adapted from Thomas Pynchon’s 1990 novel Vineland, although Anderson’s screenplay reshapes the source material around its own characters and story. One Battle After Another won six Oscars overall, including Best Picture, Best Director, Best Adapted Screenplay, Best Film Editing, and the first-ever Best Casting award.