William Jefferies

William M. Jefferies was a human Starfleet Admiral in the 2230s and 2240s. He, along with Captain Robert April, was a key supporter of the development of the Constitution class starships. Jefferies supervised the construction of the USS Constitution at the San Francisco Fleet Yards. (TOS novel: Final Frontier).

In 2242, Jefferies took the almost-finished Constitution out of drydock and raced to the Donatu system to take part in the Battle of Donatu V. (TOS novel: Errand of Vengeance, #2: Killing Blow).