Frank Anthony Grillo is an American actor. He is best known for playing Brock Rumlow in the Marvel Cinematic Universe films Captain America: The Winter Soldier (2014), Captain America: Civil War (2016), Avengers: Endgame (2019), and animated series What If...? (2021). He had his first leading role in the action-horror film The Purge: Anarchy (2014), portraying Sergeant Leo Barnes, a role he reprised in The Purge: Election Year (2016), and has also appeared in Warrior (2011), The Grey (2012), End of Watch (2012), Zero Dark Thirty (2012), Wolf Warrior 2 and Wheelman (both 2017), and Boss Level (2021). Grillo's television work includes the lead role in Kingdom (2014–2017) and recurring roles in Battery Park (2000), For the People (2002–2003), The Shield (2002–2003), Prison Break (2005–2006), Blind Justice (2005), The Kill Point (2007) and Billions (2020).