A brilliant astrophysicist and one of the world's leading experts on the Stargate, Dr. Meredith Rodney McKay is a member of the Atlantis base's lead reconnaissance unit, under the command of Lt. Colonel John Sheppard. As a child McKay always wanted to be a pianist, but his teacher discouraged him from continuing to practice, believing he had no sense of the art. McKay turned to science because he thought it would be the farthest away from his previous pursuits -- but he discovered it was just as much of an art as anything else.
While posted at Area 51 on the Air Force payroll, McKay was assigned to work with a computer model of the Antarctic Stargate. His first chance to see the "real thing" came during a crisis at the S.G.C. when Teal'c was trapped within the Stargate's temporary memory buffer. After meeting Samantha Carter, also an astrophysicist and his counterpart at Stargate Command, it became evident that he and she got off on the wrong foot, despite physical attractions shared by both. Arrogant and condescending by personality, McKay was insistent that the Stargate's crystal memory did not contain the remains of Teal'c, and pushed for the Stargate program to recommence immediately -- destroying any chance of rescuing the Jaffa.
McKay turned out to be wrong, and with aid from a Goa'uld Teal'c was recovered. After the incident, he was swiftly reassigned to Russia to advise their new naquadah reactor program. Carter was not sad to see him go. He returned less than a year later, when his services were required to solve yet another gate-related crisis at the S.G.C. McKay arrived to learn that the gate had been open long past its 38-minute limit; the Goa'uld Anubis was using a weapon to destroy the gate, and Earth along with it.
With help from a somewhat hostile Major Carter -- whom he found both increasingly attractive and worthy of his respect -- they devised a plan to save Earth by sending the Stargate away from the planet through hyperspace. McKay and Carter had made a good team, saving the Earth from certain destruction. Carter finally acknowledged to McKay that she did, indeed, find him attractive, before he was dismissed from the facility after a job well-done.
McKay was later assigned to the Atlantus outpost left behind by the Ancients in Antarctica, where he quickly became an expert on Ancient technology and pioneered the interface between human and Ancient technology. He was disturbed to learn that he is not among those who possess a very rare gene which allows some -- including Sheppard and McKay's friend and colleague Carson Beckett -- to operate Ancient technology intuitively. But Dr. Beckett's gene therapy has helped there -- after allowing himself to be a test subject, McKay has found that he can activate Ancient devices.
McKay joined Dr. Elizabeth Weir's expedition to find the lost city of Atlantis in the Pegasus Galaxy, only to learn that they do not have the power to return home to Earth. He joined up as a member of Sheppard's off-world reconnaissance unit, and the two quickly became friends (though they drive each other crazy).
Rodney has one sister, Jeannie, who is married with a young daughter. The two were estranged for several years, but a need arising from the Atlantis expedition forced Rodney to get back in touch with his sister -- who also has a brilliant scientific mind.
48 Hours - McKay attempts to thwart Carter's plans to save Teal'c, believing that he is already dead. When Teal'c is saved, McKay is sent to Russia to help them develop naquadah generator technology.
Redemption, Part 1 - Dr. McKay returns to the S.G.C. to help save the planet when Anubis turns the Stargate into a doomsday bomb.
Redemption, Part 2 - Carter and McKay share their mutual affection for each other when Earth is saved from Anubis's attack.
Rising, Part 1 - McKay studies Ancient technology at the Antarctic base before joining the expedition to Pegasus -- where he sees the doom they all face if they don't find a new power source for Atlantis.
Hide and Seek - After Beckett's gene therapy leaves McKay trapped under an Ancient shield device, McKay worries about starving to death. But he soon realizes he is the only one who can save the city from an alien entity.
Hot Zone - Rodney faces his own mortality at the hands of a nanite virus, which prompts him to regret his broken relationship with his sister.
Letters From Pegasus - On the eve of war with the Wraith, Rodney records a heartfelt message to his sister back home.
Duet - An encounter with Wraith technology leaves the mind of a female security officer stuck in McKay's head, as Rodney seeks to pursue a relationship with a woman on the base.
Trinity - Overconfident that he can solve a problem even the Ancients could not, McKay works with an experimental power generator ... and destroys most of a solar system when he cannot shut it down.
Grace Under Pressure - While trapped in a sinking Puddle Jumper beneath Lantea's great ocean, McKay and creates an hallucination of an old friend to help him survive.
No Man's Land - Alongside Ronon Dex, Rodney finds himself a prisoner and soon-to-be snack of the duplicitous Wraith.
The Pegasus Project - McKay joins Sam Carter and SG-1 on a mission to thwart the Ori's invasion plans by connecting to the Supergate from the Pegasus Galaxy.
McKay and Mrs. Miller - When his equally brilliant sister devises a math proof that could make his own project possible, Rodney must return to Earth and reconcile with her.
Tao of Rodney - An Ancient device turns McKay into a highly advanced human, vastly increasingly his intelligence -- and threatening to kill him.
The Game - When McKay and Sheppard learn that their video game has been controlling a real civilization, Rodney discovers that he is regarded by his "people" virtually as a god.
Sunday - Rodney and the rest of the team suffer a great personal loss when Carson Beckett is killed in the line of duty. Rodney continues to pursue Katie Brown.
Miller's Crossing - McKay travels back to Earth after his sister is kidnapped at gunpoint, only to get captured himself.
Be All My Sins Remember'd - McKay comes up with a plan to finally deal with the Asurans once and for all, and creates Fran, a Friendly Replicator ANdroid.
Quarantine - Trapped in a lab with Katie Brown, when a malfunction causes the computer to lockdown Atlantis, McKay pours his heart out to her.
The Last Man - Forty-eight thousand years into an alternate future, a holographic McKay helps Sheppard get back to his own timeline.
The Shrine - McKay loses all his knowledge and memories, reverting to a child-like state, after an alien organism invades his brain, and only radical surgery can save him.
First Contact - On discovering a long hidden laboratory in Atlantis, Rodney McKay and the visiting Daniel Jackson inadvertently trigger a homing beacon that attracts the attention of a powerful race.
The Lost Tribe - Trapped with Daniel Jackson on M6H-987, Rodney has to find, and shut down, the Attero Device.
Brain Storm - On Earth with Jennifer Keller to witness the triumph of Malcolm Tunney, a scientific rival, over global warming, McKay instead finds himself in a race to shut the machine down when it gets out of control, and Jennifer surprises him with some personal information.
Enemy at the Gate - While Rodney takes part in an attempt to sabotage the Wraith super-hive ship, his idea for a wormhole drive is used to move Atlantis to Earth.
Seizure - Rodney participates in a mission to trick the Langarans and use their Stargate to dial the Destiny, betting the planet's survival on his own skills.