At one point, a fake presidential limousine drove near the courthouse with a passenger inside wearing a Trump mask. Around the time of Trump's arrival, a man dressed as a Revolutionary soldier sang the National Anthem on a microphone; Trump supporters joined him in singing.
Anti-Trump protesters showed up as well -- one of whom wore a black-and-white striped jail uniform; another protester screamed expletives from a megaphone.
Hip-high metal barriers with yellow tape warning "US Marshal Do Not Cross" ringed the courthouse, keeping the news media and the public back from the building's entrances. There were dozens of media tents and hundreds of journalists covering the developments of the arraignment.
Metropolitan Police Department officers patrolled the area on foot and on bikes, and stationed themselves at major intersections. Police walked the perimeter of the courthouse, some with dogs searching the surrounding bushes.
Department of Homeland Security officials handed out emergency number cards to contracted security guards to report anything suspicious.
The courthouse was quiet inside ahead of Trump's arrival, with most reporters stationed in media rooms while police roamed around. However, as the arraignment neared, the action picked up with the court clearing the lobby and the halls of the courthouse, ushering reporters roaming around into the designated media rooms and the courtroom where the arraignment happened. Court security guards blocked the staircase that went to the second floor where the arraignment occurred.
Trump pleaded not guilty to all counts -- four charges related to his push to overturn the 2020 election results before and during Jan. 6.
The courthouse is located a few blocks away from the U.S. Capitol where the Jan. 6 attack took place.
ABC News' Aaron Katersky and Sam Sweeney contributed to this report.