Duluth was announced as the second team on April 5, 2023, to be a part of the inaugural season of The Arena League. The announcement was made at a press conference at the Garden Event Center in Duluth and included notable figures including the city mayor,
Emily Larson, and the league commissioner,
Tim Brown. The
DECC Arena agreed to a 3-year lease to be the home field for the team. The Harbor Monsters concluded their first season with a record of 5 wins and 3 losses, earning them a spot to host a playoff game against the Ozarks Lunkers. Following their victory against the Lunkers, the Harbor Monsters advanced to host the championship game—the inaugural ArenaMania—where they faced off against the Iowa Woo. The coin toss for ArenaMania I was conducted by Duluth's newly elected mayor, Roger J. Reinert, and the halftime show featured a performance by the rock band, Palisade. ArenaMania I was a thrilling contest, with the Harbor Monsters narrowly defeating the Iowa Woo 46–44 to become champions of The Arena League. This historic win marked the Harbor Monsters as the first professional football team in Minnesota to claim a championship in the modern era. On September 24, 2025, the Monsters announced that they would be joining Arena Football One and rebranding as the Minnesota Monsters, reviving a brand that was last used in indoor football in 1998 with the original
Minnesota Monsters. The change coincided with TAL opening an investigation into head coach Tony O'Neil and GM Steven Walters for “actions that are detrimental to the integrity of The Arena League”. The league had suspended O'Neil indefinitely just prior to the announcement of the team's move to AF1, and refused to acknowledge the legitimacy of the team's move or its sale, stating it did not have contact with the Monsters' new owner, would continue to recognize the previous owner, and does not allow teams to leave TAL as a matter of policy, stating all teams are bound to TAL "in perpetuity." Head coach
Tony O'Neil resigned his position due to a mental breakdown on October 23, 2025, with former
Cedar Rapids River Kings head coach
Daron Clark assuming the position. On December 18, the Monsters announced they were leaving DECC Arena in favor of AMSOIL Arena for the 2026 season.
Team name and logos On July 27, 2023, team owner, Brent LaBrie, announced the four finalists for the team name: Sasquatch, Norsemen, Harbor Monsters, and Lakers. The represented city name was also narrowed down to four finalists: Twin Ports, Minnesota, Lake Superior, and Duluth. The Duluth Harbor Monsters’ team name and logo were officially unveiled on August 24, 2023, during a press conference at the DECC. The name originated from a "Name-the-Team" contest that garnered nearly 2,000 submissions. The final four names underwent a fan vote, resulting in an almost three-way tie between Sasquatch, Norsemen, and Harbor Monsters, with Harbor Monsters emerging victorious. The team's logo, created by Ryan Foose of Foose Sports, draws inspiration from the mythical Mishipeshu, the legendary underwater panther of Lake Superior. The design incorporates blue and gold, paying tribute to Minnesota's state colors. Minnesota resident Ian Thorpe, who submitted the winning name, earned the honor of naming the team. ==Roster==