Born on the pirate vessel, The Grim Reaper, in 2136 CE, Travis was the son of a young news reporter being held as a hostage; his father had been killed by the kidnappers a month before his birth. Dunn was raised on the Grim Reaper until the age of twelve, where he watched his captors rape his mother and beat him.
When he was twelve years old, the Grim Reaper was raided by soldiers in the Alliance Corps of Privateers, a group of marines dedicated to hunting down and eradicating pirates and smugglers in Alliance Space. Dunn and his mother were taken to New York City on Earth, where they lived in an Alliance-run shelter, with Dunn recieving an education.
Seven years later when Dunn was twenty one in 2157 CE and due to his lack of formal education he failed to be able to procure a job he joined the Alliance Marine Corps and was soon inducted into the 467th Systems Alliance Marine Tactical-Reconnaissance Division also known as the Systems Alliance Marine Recon, one of the most prestigious subdivisions of the Alliance Marines.
In January 2158 CE, Dunn passed the 467th's specialized training on Guam and after scoring a 198 out of 200, he became a sniper. He was deployed as one of the first soldiers to the Citadel where he served in the second platoon of the third brigade of the 467th which for the next ten years would guard human VIPs on the Citadel until the Alliance Rangers replaced the Recon Marines at the prestigious posting.
After very little action in which Dunn had killed only two would-be assassins in ten years, he was transfered to an assignment on the SSV Chickamuaga, a frigate in the expeditionary corps of the Alliance Navy, which scoured for planets of potential mining or colonization value to the Alliance.
Dunn was part of the ship's reconnaissance complement and scoured multiple worlds with his squad, often going solo on barren planets to provide overwatch. This made him a lone wolf and very self-reliant. In a scouting operation on Domanca, a barren desert world believed to be rich in element zero, Dunn made his way to the top of a ridge to provide strategic overwatch for his team.
However he had moved out of the radio grid and missed an order to fall back to extraction. For two days he was left alone on a barren world that was occupied by big-game and very dangerous reptiles, and batarian slavers. Dunn managed to take down an entire camp from a ridge, killing nineteen batarians and accessing a radio to call for backup to the crew of the Chickamuaga, who were looking for him.
After the incident he was promoted to Gunnery Sergeant and continued to be a part of the Chickamuaga's garrison until 2176 CE when he was deployed to help stop anarchy on the krogan border world Gomainda as part of a multi species coalition who's goal was to ensure the krogan did not move on Citadel Space.
Dunn was given command of Wolf Team, a six-man group where he replaced the conventional radio operator as a specialist. Gunning from a customized Valkyrie gunship with side skids, Dunn provided overwatch and support to his team as they worked with a turian platoon to push back the makeshift krogan paramilitary force who had three platoons holding a place of interest, a salarian military base from which the Salarian Union had sent soldiers for two hundred years to watch the krogan forces.
Using his Calico to deadly effect, Dunn racked up twenty seven kills in two hours and suffered no losses from his team. This continued until his aeriel sniping position was shot down and Dunn with it. The gunship crashed in the base's courtyard and Dunn managed to procure a small armor piercing sub machine gun which he used to kill nine krogan before his team arrived and saved him.
Due to his legs being broke, Dunn had to be dragged to a medical dropship while his team did the rest. The wounded soldier was then brought to the medical ship, SSV Missouri, named for the Missouri River on Earth which was in orbit over the beseiged planet.
When Dunn awoke the next day, it was predicted he would never walk again. Upon hearing this Dunn, to his great pain sprung from his bed and walked claiming otherwise. This showed to a lieutenent visiting his corporal brother, both of whom were in the 467th that Dunn was a strong and tough soldier.
The officer, Lieutenent Zabreka had Dunn and his team transferred to his unit, something that may have saved his career.