Soontir Fel was born on Corellia to a family of farmers. He first learned to fly by racing airspeeders on his homeworld, and later received more formal instruction at the Imperial Academy on Carida. This caused some consternation for his family, as he was due to be a witness for a trial at the time he left Corellia. Fel quickly became one of the top flying students at the Academy, rivaled only by Cadet Han Solo. After graduating as a lieutenant, Fel served in the 37th Imperial Fighter Group, and later taking command of one of its squadrons. He and his men earned a reputation for fierceness.
After his second tour of duty, Fel served as a capital ship commander and a flight instructor. Unbeknownst to him, several of his students (including Biggs Darklighter and Derek "Hobbie" Klivian) planned on defecting to the Rebel Alliance. When they did so, Fel was transferred to the 181st Imperial Fighter Group, which had a reputation for being the Empire's worst pilots.
Under Fel's leadership, the 181st underwent a complete turnaround, and its reputation improved accordingly. At a ceremony where he was promoted to the rank of major, Fel met actress Wynssa Starflare- born Syal Antilles, sister of Rebel ace Wedge Antilles. Fel and Starflare quickly fell in love, and were eventually married. Shortly before their marriage, Starflare admitted her true identity to Fel, who promised to keep it a secret.
Approximately nine months after the death of Palpatine at the Battle of Endor, Fel's 181st would cross paths with Wedge Antilles' Rogue Squadron at the Battle of Brentaal IV. Although Fel and his men downed several fighters, Fel himself was captured by New Republic forces after an ion cannon shot from Horton Salm's Y-wing disabled his fighter. During an interrogation with Wedge, where he revealed they were brothers-in-law, Fel announced he had lost faith in the Empire, and made a shocking proposal: If the New Republic could help him find his long-lost wife, he would fight on their side.
Wedge agreed to Fel's proposal, and assigned him to Rogue Squadron. Although several other members of the squadron were distrustful of Fel, he served faithfully at the Battles of Axxila and Ciutric. Five months after his defection, Fel and his wife, who had dropped her pseudonym, were indeed reunited.
The Empire was enraged at Fel's defection, and launched a propaganda campaign vilifying him. This culminated in a successful plan by Grand Admiral Thrawn to kidnap him, which led the New Republic to believe he had been killed by the Empire.
In actuality, Fel had been taken to Thrawn's secret base on the planet Nirauan, where Fel was convinced that Thrawn's "Empire of the Hand" represented the Empire he had once fought for. He served this Empire for several years, until Thrawn set out to revitalize the Galactic Empire.
Living with his wife among the Chiss in the Unknown Regions, Fel would become a father to several children, most notably Jagged Fel. Named for Syal's father, he would in later years become the husband of Jaina Solo.