Matthew Louis Shear is an American actor known for his work in independent film and frequent collaborations with director Noah Baumbach. He began his career with a small role in Taking Woodstock (2009) and appeared in Mistress America (2015), The Meyerowitz Stories (New and Selected) (2017), and Marriage Story (2019), and played Lucius Isaacson on The Alienist (2018–2020). In 2025, he made his directorial debut with Fantasy Life, which he also wrote and starred in.