Thomas Hammock leaving NIU for position with NFL's Seattle Seahawks

Northern Illinois coach Thomas Hammock is leaving for the NFL, accepting a position as an administrative offensive assistant with the Seattle Seahawks, sources told On3.

An NIU alum where he was a star running back, Hammock was 35-47 in seven years and led the Huskies to the 2021 MAC title. 

Defensive coordinator Rob Harley will be NIU’s interim coach, sources said. Maintaining continuity among the coaching staff and keeping the team together, along with success in the transfer portal and recruiting, were key components in promoting Harley, a source said.

The Huskies begin play in the Mountain West this fall as a football-only member after leaving the MAC.

Under Hammock, the Huskies had winning seasons in three of the past five years and also went to bowl games in 2021, 2023 and 2024. 

In 2024, NIU pulled off college football’s biggest upset, shocking 28½-point favorite and No. 5-ranked Notre Dame 16-14 in South Bend.

Harley came to NIU in 2025 after four years as an assistant head coach/defensive coordinator at Arkansas State. Harley also previously was an assistant at Pitt, FIU, Michigan State and Ohio Dominican.

With Harley as DC last season, NIU had the MAC’s second-best pass defense, allowing only 174 yards per game, and ranked sixth nationally, allowing only 11 TD passes.

With Hammock’s departure and Harley’s promotion, NIU is expected to add more staff members.