Born into a ComStar family, Tucker and his sister Patricia both chose to continue the Harwells' seven generations of service to the organization, stretching back well before the ComStar Schism and Jihad.
Showing an almost prodigious understanding of most technical concepts from a young age, Tucker earned his doctorate in Hyperpulse Generator systems at the age of twenty-one, receiving a posting to ComStar's headquarters in Sydney on Terra as an Adept Alpha (Hyperpulse Generator Operation) a mere three months before Gray Monday in 3132. As ComStar desperately scrambled to restore the HPG network, Tucker's almost preternatural skills with Hyperspace Generator Systems and the theories of Thomas Kearny and Takayoshi Fuchida resulted in him being assigned to undergo advanced courses at the Cassie DeBurke Institute for Hyperspatial Studies by his former teacher Precentor Carole Ackerman. 
His performance at the DeBurke Institute attracted the attention of Ackerman's superior and Director of Special Projects, Precentor Malcolm Buhl. Impressed with the young man's reputation, Buhl dispatched Tucker to restore the HPG on the Republic of the Sphere world of Wyatt in 3135. Much to everyone's amazement and joy, Tucker succeeded and found himself in the midst of a three-way conflict between the Clan Nova Cat splinter group the Spirit Cats, defensive Republic of the Sphere troops, and an invasion force from the Oriente Protectorate attempting to secure his knowledge and the Wyatt HPG.
However Tucker was instead "rescued" by his sister and elements of the First Division of the secretly rebuilt Com Guard, kidnapped by the fanatical Blessed Order faction within the post-Jihad era ComStar. Tucker was forced to aid the faction in developing a method to repair the remaining non-functional HPGs for their benefit. While Tucker's methods of restoring the Wyatt HPG were disseminated after his disappearance, they only worked briefly if at all, making locating the young Adept even more vital. 
Tucker was moved, with his sister, to the Omega One secret base, on Luyten 68-28, working to resolve the HPG Blackout. Despite the fact he was sabotaging the progress, he was unable to find the reason behind the Blackout, or a solution to it. His solution for HPG Wyatt - a change of frequency only work for that HPG. Not too much later, ROM uncovered his treason, and begun watching him closely, and using him to recover data from old radioactive archives recovered in system. From these archives Tucker he found references the Blakist called "Clarion Case Protocol". Buhl, assuming the HPG Blackout was caused by a virus, ordered the construction of two new HPG stations, what he called "Polar Network", expecting to free them from virus. The plan was to use these freshly constructed stations as the template to restore the HPG Network. Buhl doesn't trust Tucker due to the later's sabotaging efforts, and when Tucker tried to warn him to shut the stations down, he was ignored. Both HPG were burned to the ground. Buhl ignored the continued claims of innocence from Tucker, and instead assumed Tucker had been the one who sabotaged the HPGs. Buhl and ordered Tucker's own sister to interrogate him. She proved to be a religious zealot with no qualms in using Blakist technology to torture her brother without mercy. Tucker suffered brain damage, losing parts of his mind. After he awakened on a hospital a new interrogator, a woman named "Sandra Whitfield", began torturing him. Tucker managed to escape from his cell after murdering an adept and a ROM agent. When finally confronted by Whitfield, she told him she was the knight Alexi Holt, who had infiltrated the Order to rescue him. Despite his doubts (Patricia had made him believe before that Holt was there to rescue him, which had been a lie) he joined her and they stole a shuttle. After escaping to space, Alexi collided with a ComStar fighter pursuing them, and both exploded.
However, both were alive and took refuge on an old derelict Blakist space station. They reactivated it enough to survive, and Tucker wrote a program to communicate his location to the Republic. When looking through Blakist archives, Tucker made an incredible discovery: "Clarion Note" was a Blakist project, consisting in using a Super HPG to cause a complete communications blackout. Their survival was discovered by Patricia, and an assault team was dispatch to the space station. Tucker and Alexi stole the assault team's shuttle and fled to the surface of the planet. They went to ground, barely surviving until Republic of the Sphere DropShips arrive to rescue them. After being rescued, and confirming Patricia's death in the fight, Tucker was returned to Earth and taken to a hospital. When he recovered, he was put in command of "Project Sunlight", a unit with the objective to find a solution to the HPG Blackout. Using Alexi Holt's access code on the recovered Clarion files, he made an incredible discovery: The Blackout had been caused by Devlin Stone. Refusing to listen to Holt, Tucker announced his finding before fleeing.
- Era Report: 3145, p. 117 "Major Personas - ComStar - Tucker Harwell"
- Era Report: 3145, p. 13 "History and Review - The Fall of Darkness"
- A bonfire of Worlds p. 12
- A bonfire of Worlds p. 18
- A bonfire of Worlds p. 53
- A bonfire of Worlds p. 95
- A bonfire of Worlds p. 102
- A Bonfire of Worlds p. 124
- A Bonfire of Worlds p. 142
- A Bonfire of World p. 251
- Field Manual: 3145, p. 140