WASHINGTON—Former Trump strategist Steve Bannon surrendered to law enforcement Monday and was set to make his first court appearance after a federal grand jury indicted him on criminal contempt of Congress charges for defying a subpoena from the House committee investigating the Jan. 6 attack on the U.S. Capitol.

Mr. Bannon, 67 years old, turned himself in at the Federal Bureau of Investigation’s Washington office just before 10 a.m. Monday. Addressing television cameras, Mr. Bannon said, “We’re taking down the Biden regime.”