A Tower Local Controller reported a taxiing aircraft entered the runway without clearance at the same time another aircraft was commencing its takeoff roll; resulting in a takeoff clearance cancellation.

Narrative

Working Local Control North. Aircraft X was given takeoff clearance on Runway 8R. Runways at the time were clear; aircraft read back clearance and began take off roll. Next aircraft in cue was given line up and wait clearance to follow in sequence. During this time; Aircraft Y being began their taxi to Runway 8R via taxiway M. They appeared to have taxied via M10 intersection and failed to turn onto [taxiway] Mike; and then they proceeded to continue forward on M10 and onto Runway 8R. Aircraft X at this time was about 1/4 of the way down Runway 8R on their takeoff roll; when the ASDE-X alerted; the management alerted as well as the controllers noticing what began to unfold. Having seen these events; I gave Aircraft X take off cancellation clearance and instructed them to stop/hold position. After aircraft were both stopped; Aircraft X was then instructed to taxi off the Runway; taxi onto the adjacent taxiway and put in a location to assess their status. Aircraft Y was also taxied off the Runway by Ground Control and given a warning along with further taxi instructions. Once the Runways were cleared; operations continued as normal. Aircraft X later returned to the terminal for company required checks without further incident. Suggestions: Further vigilance can be maintained; but controllers and management on duty already practice increased awareness with aircraft movement on the field. The scan for the Local Control North position is a continuous movement checking multiple points in succession. It's hard to predict [an] incident such as this even with a hypervigilant scan. Good situational awareness maintained by the oversight and neighboring controllers.