Trondheim Marathon began on November 2, 1969, as a student marathon with 12 male finishers. The following year, 15 men participated. By 1975, there were 39 participants, and in 1982, 45 runners plus a recreational class with 23 participants. In 1983, the newspaper reported that over 300 runners completed the marathon. Trondheim Marathon is the oldest marathon in Norway and has been held continuously since its inception. The event was originally organized by the students at NTH in collaboration with the Marathon Club, later by the Marathon Club alone, and then by Nidelv I.L. Since 2011, Nidelv I.L. has partnered with the Corporate Sports Association in Mid-Norway under the Trondheim Weekend umbrella. In 2015, support from Trondheim Weekend ceased, and Nidelv I.L. and the Corporate Sports Association took over the full responsibility for organizing the event.

The board of the Marathon Club originally consisted of Jan Holth, Torleif Rekkebo, and Tom Myran. The student marathon was renamed Trondheim Marathon, likely in 1978.

Since then, the event has set new participation records year after year, with 2025 as the biggest so far – a total of 14,623 participants.