His name is Garven Dreis and was Red Leader in the Battle of Yavin.
In terms of Star Wars now "official" canon there is not much out there but he was given extensive backstory in the EU (extended universe)
Garven "Dave" Dreis was the commander of Red Squadron, and a T-65 X-wing starfighter pilot for the Alliance to Restore the Republic. Hailing from the planet Virujansi in the Inner Rim, Dreis originally served with the Rarefied Air Cavalry, fighting in the Clone Wars that took place from 22 BBY to 19 BBY. During the Battle of Virujansi, Dreis had the opportunity to fly alongside the "Hero With No Fear," Anakin Skywalker. In the wake of the Clone Wars and the subsequent Declaration of a New Order, Dreis joined the Rebel Alliance—an organization dedicated to shaking the Galactic Empire's hold on the galaxy—after seeing the Empire commit atrocities on his homeworld.
For more details as to his "Legends" / non-canon backstory - this is probably the best place to go:
Regarding 'non-canon' or "Legends" status - Disney / LucasFilm Story Group have stated that the EU is no longer an official source of information. The only official canon is comprised of all films, tv shows (Clone Wars / Rebels) and new books and comics