Played by: Michael Dorn
Position/occupation: Strategic Operations Officer (season 4 onward), Deep Space Nine
Rank/title: Lt. Commander
Birthplace or childhood home: Qo'Nos; Khitomer (as small child); Gault; Earth
Parents: Mogh (biological father, deceased); Sergei Rozhenko (adoptive human father); Helena Rozhenko (adoptive human mother)
Siblings: Kurn (biological brother); Nikolai Rozhenko (foster brother)
Spouses: K'Ehleyr (1st "mate"); Jadzia Dax
Child: Alexander Rozhenko (son by K'Ehleyr)
Hobbies/likes/interests: Worf preferred mostly Klingon food and drink, except prune juice, his favorite beverage. He enjoyed Klingon martial arts, and held a morning exercise class.
Friends elsewhere: The Enterprise officers (Capt. Picard, Cmdr. Riker, Deanna Troi, Lt. Cmdr. Data, Lt. Cmdr. Geordi La Forge, Dr. Beverly Crusher)
The first of his people to serve in Starfleet, Worf was born on Qo'Nos, and as a small child was on the outpost of Khitomer when it was attacked by the Romulans. His parents were killed, but Worf survived and was found and raised by a human Starfleet couple, Sergei and Helena Rozhenko.
Worf spent much of his childhood on the sparsely-populated farm world of Gault. At 13, he was captain of his school's soccer team, and accidentally killed an opponent during a championship game. This explained why he tended to be more controlled and disciplined than the average Klingon. He attended Starfleet Academy, and later became an officer on the USS Enterprise-D, where he served first as tactical officer, then as security chief.
In his Academy days, Worf had an affair with a half-Klingon, half-human woman named K'Ehleyr, with whom he was reunited briefly on the Enterprise; they conceived their son Alexander, though this was unknown to Worf at the time ("The Emissary" [TNG]). Two years later, K'Ehleyr presented him with Alexander, shortly before being murdered by Duras ("Reunion" [TNG]). Alexander then lived on and off with Worf on the Enterprise.
After the ship's destruction (Star Trek: Generations [movie]), Worf went into contemplation on Boreth until 2372, when he was assigned to DS9 to investigate Klingon Empire activity. After Gowron disowned him for not siding with the Empire during the invasion of Cardassia, Worf stayed on DS9 as Strategic Operations Officer, switching from security to command ("The Way of the Warrior").
Worf had trouble adjusting to life on the station. In "Hippocratic Oath", disapproving of Odo's security methods, he ruined a sting Odo had planned. Later, in "Bar Association", he took up residence on the Defiant. Worf commanded the Defiant for the first time when Sisko was injured in battle with the Jem'Hadar in "Starship Down". He also went on a quest with Dax and Kor to the Gamma Quadrant to find Kahless' legendary bat'leth. They found it, but ended up setting it adrift ("The Sword of Kahless").
Worf faced a tough decision in "Sons of Mogh", when Kurn showed up on the station demanding Mauk-to'Vor, a ritual killing that would restore his lost honor. Worf ended up having Kurn's memory wiped so that his brother could begin a new life. In "Rules of Engagement", after destroying a civilian Klingon ship during a battle, Worf was subjected to an extradition hearing; but it was proven to be a setup by the Klingon Empire.
In "Looking for Par'Mach in All the Wrong Places", Worf fell for Grilka, but aided Quark in winning her, and then Dax made her own feelings for Worf known. They began a romantic relationship; and in "Let He Who is Without Sin...", they went to Risa, where Worf disapproved of the lifestyle and briefly aided Pascal Fullerton's movement.
A few months later, accompanied by Garak, Worf went to investigate a signal from the Gamma Quadrant, and was captured by the Jem'Hadar. While in the prison camp, he fought several Jem'Hadar in single combat, and became friends with Martok ("In Purgatory's Shadow"/"By Inferno's Light"). Soon afterwards, Worf was first officer under Martok on the Rotarran, and after challenging him, was accepted into Martok's house, as his brother ("Soldiers of the Empire"). When Starfleet retreated from DS9 in "Call to Arms", Worf went with Martok on the Rotarran, after he and Dax vowed they would marry when the war was over.
While serving on the Rotarran, Worf was reunited with his estranged son Alexander, now a recruit in the Klingon Defense Forces. They finally reconciled, and Alexander joined the House of Martok as well ("Sons and Daughters"). For the battle to retake DS9, Worf went with Martok to talk Gowron into sending ships to aid Sisko's fleet, and arrived with said ships just in time to turn the tide of the battle ("Favor the Bold"/"Sacrifice of Angels").
Worf and Jadzia Dax were married on DS9 ("You Are Cordially Invited"), and Worf moved back into quarters on the station, which he shared with Dax. On a mission with her to aid a defecting Cardassian informant, Worf chose to save his critically injured wife rather than make the rendezvous with the informant. Sisko later told him that due to the need for secrecy, Worf would not be court-martialed, but he would probably never get his own command ("Change of Heart"). Later, in "Time's Orphan", Worf tried to prove his worthiness as a father to Jadzia, by babysitting Kirayoshi.
Worf and Jadzia were planning to have a baby, when Worf went on the mission to take Chin'toka; but after the battle, he learned that Jadzia had been mortally injured by the Dukat/pah-wraith. Worf returned in time to say farewell before she died ("Tears of the Prophets").
A grieving Worf accompanied Martok on a dangerous mission to Monak IV, to win a place for Jadzia in StoVoKor ("Image in the Sand"/"Shadows and Symbols"). When Ezri Dax arrived on the station, Worf was cold to her at first, believing that befriending her would dishonor Jadzia's memory; but he came to realize that Jadzia would want him to treat Ezri fairly, and finally accepted her presence ("Afterimage").
Not long after, Worf was approached by Kor to get him a place in Martok's small raider fleet. When Worf planned to sacrifice himself to delay the Jem'Hadar pursuing the fleet, Kor knocked him out and went instead ("Once More Unto the Breach").
In "Penumbra", Worf was lost in an escape pod after the ship he was commanding was destroyed by the Jem'Hadar. He was found by Ezri, with whom he was then stranded. They made love, after which they were captured by the Breen. In "'Til Death Do Us Part", after an interrogation session by the Breen, Ezri murmured Julian's name, leading Worf to believe that she loved Bashir. While awaiting trial and execution on Cardassia, Worf and Ezri agreed that their indulgence had been a mistake, before they were unexpectedly helped to escape by Damar ("Strange Bedfellows"). They then returned to DS9 ("The Changing Face of Evil").
In "Tacking Into the Wind", after Gowron took over command of the Klingon fleet, Worf recognized his tactics as being designed to undermine Martok, and knew that these actions would destroy the Empire. Worf urged Martok to challenge Gowron, but Martok refused; so Worf did so himself, and killed Gowron. He was hailed as the Empire's new leader, but instead gave the robes to Martok.
Finally, in "What You Leave Behind", Worf was on the Defiant during the final assault on the Dominion, and afterwards was appointed Federation ambassador to Qo'Nos.
Other facts: His quarters with Jadzia were on Level 3, Section 27, Room 19.