Hoban "Wash" Washburne was the pilot of Serenity, a smuggling ship captained by Malcolm Reynolds. He was married to the ship's first mate, Zoë Alleyne Washburne.
Raised on a planet with pollution so thick the stars were not visible, Wash became a pilot in part to see the sky beyond his home. Wash was second in his class. Mr. Universe, Wash's friend in flight school, was top of the class, since he hacked the records. In order to buy Wash's silence (and save himself from a threat of bodily injury at the hands of Wash), Mr. Universe offered Wash his services whenever they were needed.
Wash then traveled widely, visiting odd worlds where, for example, juggling goslings was the principal form of recreation. His skills as a pilot grew, and by the time Wash met Malcolm Reynolds, his reputation had grown to the point where he was actively courted by multiple captains in search of a good pilot (Mal tells Zoë that Wash has a list of recommendations "as long as [his] leg" when Zoë expresses her dislike of Wash). Wash accepted Mal's offer, and in the course of time, fell in love with and eventually married Reynolds' second-in-command, Zoë. This pairing was especially ironic, given that Zoë's first impression of Wash was one of immediate dislike and distrust. The two had a passionate and strong relationship, despite Wash's occasional concern over Zoë's strong personality and her tendency to assume the more aggressive, traditionally male role in the marriage, a concern compounded by Zoë's fierce loyalty and devotion to Mal. However, he does prove his loyalty when Saffron, a young woman posing as Mal's wife in order to take over the ship, attempted to seduce him by telling him the myth of the Earth-That-Was and how the stars joined it. He denied her, saying he had a "beautiful wife who can kill me with her pinky."
A laid-back guy with a dry and occasionally laconic sense of humor, Wash tended to represent the pragmatic, cut-and-run opinion in any shipboard debate, and often served as the calming influence in heated arguments. His actions sometimes appeared cowardly (or at least less than heroic), but Wash had proven his resolve and willingness to both put himself in harm's way and do violence on behalf of his friends on many occasions. His loyalty to his fellow crew was unshakable, as is shown when he insisted on rescuing Mal from the clutches of the crime lord Adelai Niska, despite clashing with Mal over Zoë earlier and having been severely tortured by Niska to the point of barely being able to stand.
As a pilot, Wash's flying style oscillated between near panic and a Zen-like calm. The attitude he conveyed seemed to be in inverse proportion to the degree of danger he believed he and the ship were in at any particular moment, acting the most calm when facing the greatest danger. His mantra, which he quietly recited during a highly stressful situation, was "I am a leaf on the wind; watch how I soar," although Wash apparently did not know what it meant.
Wash kept a collection of toy dinosaurs in the ship's cockpit and played with them during lulls in the action.