Harrison's firing comes after a disappointing 3-8 start to the 2025-26 season, which diminished much of the hope generated by Dallas' 2024 Finals appearance and the selection of top prospect Cooper Flagg with the first overall pick in June.

"This move demonstrates our ongoing dedication to creating a championship-winning organization that serves our players, partners, and most importantly, our fans," Mavericks owner Patrick Dumont said in an official statement.

Doncic trade fallout

Harrison’s term was largely defined by the February trade sending perennial All-NBA star and MVP candidate Doncic to the Lakers in return for Anthony Davis and draft picks.

This major trade, described internally as a move to rebalance the roster, has since faced widespread criticism.

After helping Los Angeles secure 50 wins and the third seed in the Western Conference last season, Doncic has started this season strong, leading the league with 37.1 points per game.

In contrast, Davis has struggled with injuries since joining Dallas, exiting the October 29 game at Indiana due to a mild calf strain and has missed six straight games as the team monitors his recovery.

Despite promising moments from 18-year-old Flagg, Dallas has lost five of their last six games, and fan dissatisfaction has grown, with chants of 'Fire Nico!' resonating at the American Airlines Center.

Dumont’s choice to make a change before mid-November highlights the team’s poor performance and an increasing urgency to stabilize the franchise’s future.

Harrison, 52, was hired in 2021 and earned a multi-year contract extension in June 2024 after helping assemble the Mavericks team that reached the 2024 NBA Finals. He publicly supported the Doncic trade as a necessary progression, stating in April, "We have no regrets."

"Part of my responsibility is to make the best decisions for the Mavericks, not just for today but also for the future," he said. "Some choices I make might be unpopular."

Assistants Michael Finley and Matt Riccardi will act as co-interim general managers, the Mavericks announced, as they launch a "comprehensive search" for a permanent GM.