Spock was a Vulcan Male lieutenant commander in the Alliance Fleet who worked as chief science officer aboard the Defiant-class frigate Defiant. When the Galactic Empire began occupying his homeworld in 0 ABY, he joined the Alliance to Restore the Republic fleet and convinced the Alliance Leadership to launch an attack to regain the planet. He led the Alliance Fleet blockade of the planet, and, due to his preformance in the battle, was promoted to lieutenant commander and became the chief science officer onboard the Defiant-class frigate Defiant.