Duvall was a Starfleet officer during the mid-22nd century.

In 2144, Duvall was a pilot in the NX Project. Along with Commanders Gardner, A.G. Robinson, and Jonathan Archer, he competed for the position as pilot in the effort to break the warp two barrier in the NX-Alpha. Ultimately, however, Robinson was chosen to conduct the flight. The next year, Duvall became the first Human to break warp three, while piloting the NX-Delta. (ENT: "First Flight")

In 2151, Duvall was promoted to captain and given command of the Shenandoah. News of Duvall's promotion reached Jonathan Archer and the crew of the Enterprise NX-01, causing Archer to remark, "thank God we're a hundred light years away." (ENT: "Silent Enemy")