Wes Janson began his career with the Rebel Alliance as a member of the Tierfon Yellow Aces, a Y-Wing training squadron. In one of his early missions he had to shoot down a fellow pilot because he lost his nerve and nearly revealed the entire squadron to the enemy. It was Janson's first kill and weighs heavily on him to this day. Within the Tierfon Yellow Aces Janson met and became close friends with Jek 'Piggy' Porkins who would join the attack on the first Death Star only because Janson was too ill.
After the destruction of Alderaan the best pilots from various units were to assemble at Yavin to attack the Death Star, Janson was supposed to go but was struck with Hesken Fever. His replacement was Porkins who ended up dying in the assault on the Death Star, Janson can't help but wonder how things might have been different had he been there instead of Piggy.
After the battle of Yavin Janson joined Rogue Squadron and made friends with many of the pilots particularly Wedge Antilles and they became each others wingmen. During the Imperial attack on the Rebel base on Hoth Janson flew as Wedge Antilles' rear gunner and together they brought down the first AT-AT with the snowpeeder's harpoon and tow cable. As part of Rogue Squadron he also flew at the Battle of Endor and became a mainstay of the Rogues though he took some time to instruct new pilots and help Wedge found Wraith Squadron.