The Arena Football League and Monumental Sports & Entertainment both announced on November 14, 2016, that it had granted an expansion franchise to begin play for the 2017 season in Baltimore.

[1] Monumental Sports & Entertainment is operated by Ted Leonsis, the majority owner, who had also previously been granted an expansion team in the Washington Valor to begin play the same season.

Leonsis purchased the franchise rights from the Baltimore Lightning, an established semi-pro team that had intended to join the AFL.

[3] On January 25, 2017, the team was officially announced as the Baltimore Brigade, named for the military history and in reference to the War of 1812 and the inspiration for the penning of the poem that would later become known as "The Star-Spangled Banner", the U.S.A.'s national anthem.

In a January 2019 interview with Forbes, Leonsis noted that the Brigade was not particularly successful in regard to finances, and that he mainly used the team and its Washington counterpart to experiment with ideas to later use with his more prominent sports properties such as the Wizards, Mystics and Capitals.