Star Trek: Every First Officer Ranked
1. Spock - The Original Series
Spock defined what it meant to be a first officer. Cool and logical with the ability for cunning and a penchant for command, Spock is one of the longest serving first officers in the franchise. Beginning his tenure as first officer in 1966 and remaining so, albeit with the rank of captain, until 1990, Spock was the very model of dedicated right hand man.
He is both the cause of some of Kirk's greatest woes (Amok Time) and the saviour of his captain on many occasions. He is well respected and, with the exception of Dr. McCoy, very rarely needs to be challenged. His desire to aid and to carry out the primary mission of Starfleet was legendary.
As first officer, he sought to keep his captain safe, even if it meant risking his own career to do it. He brings Pike back to Talos and rescues Kirk from Rura Penthe. The rules, which assumedly would be sacred to a Vulcan, are understood by Spock to need flexibiltiy from time to time.
He is at the top of this list not just because his tenure is the longest but also because for generations of fans, Spock simply was Star Trek. William Shatner's Kirk may truly be the definition of a leading man but Leonard Nimoy's Spock was the epitome of cool greatness. He was a very welcome addition to the Abrams reboot and he is sorely missed in real life. Live long and prosper Spock, the greatest Number One of them all.