Born in 2264, Lieutenant Commander Tuvok is amongst the older of Voyager's crew. He first joined Starfleet at the age of twenty five, and after his graduation in 2293 he was assigned to the USS Excelsior. He served on board the ship during the Khittomer crisis; during this time he came into conflict with Captain Sulu when he objected to the Captain's decision to disregard orders in order to assist his friends. After the crisis was past Tuvok continued to find it difficult to fit in with Starfleet, and in 2398 he resigned and returned to Vulcan to attempt the Kohlinar discipline.
Tuvok repeatedly failed the Kohlinar, and after six years he abandoned the discipline when he underwent Pon Farr1, instead marrying T'Pel.2 He spent the next forty five years living quietly on Vulcan, concentrating on raising a family. In 2349 Tuvok decided to return to Starfleet, having developed a more flexible attitude to alien philosophies. He served on board several ships, including the USS Wyoming,1, before becoming chief tactical officer of the USS Voyager. Whilst in this post he was ordered to infiltrate the Maquis, and he was successful in this mission. In 2371 his ship was lost in the Badlands when the Caretaker transported them to the Delta Quadrant. When Voyager followed the ship and was also abducted3, Tuvok returned to his own ship.4 He continued to serve on board Voyager for the next seven years.5 Tuvok felt that he should have become Janeway's first officer, and thought that it was a mistake on Janeway's part to promote Chakotay to the post. As a result he and Chakotay did not get along very well for several years, although eventually they began to forge a better working relationship.6
Tuvok felt himself to be somewhat isolated from the rest of the crew during much of his time on Voyager, and rarely took part in social activities. This began to change during the last couple of years of the ship's journey; Tuvok became closer to Harry Kim when he tried to teach the Ensign Vulcan emotional discipline, and the two became regular kal-toh players.7 He also developed a degree of friendship for Neelix.8
During his final year on Voyager, Tuvok developed the early stage of a degenerative neurological condition. The condition can only be cured by a mind meld with a compatible relation, and Tuvok was resigned to having his condition gradually deteriorate. However, Voyager's successful use of a Borg transwarp hub to reach Earth brought him back to his family far earlier than expected,9 and he was cured shortly afterwards.