A Colonel in the Russian military, and Russian envoy to the S.G.C.. After the Asgard ship Beliskner crashed into the Pacific Ocean with the Stargate aboard, the gate was recovered by the Russians and a short-lived, secret program set up in Siberia. More than a year later, Chekov was assigned as the country's liaison with the S.G.C.
At first, he was strongly opposed to the concept of a Stargate program completely under control by the United States, demanding Russian involvement -- and a share of the spoils. But Chekov has come to realize that Russia cannot afford the costs necessary to maintain such an expensive program itself (at the time the S.G.C. cost the United states more than $7.4 billion per year), and is content to reap the benefits of the partnership without the massive expenditure.
Chekov is extremely loyal to Russia, and is not about to let any other nation gain an upper hand without his country's permission. He has often locked horns with Colonel Jack O'Neill.
Chekov was a good friend of Colonel Zukhov, who lost his life on an alien world while secretly attempting to recover the Eye of Tiamat, an ancient device presumed (and later discovered) to be a weapon. He seems to hold SG-1 at least partially responsible for his friend's death, as the teams were on a joint mission.
Chekov's concerns were appeased when General Hammond finally authorized the addition of a Russian team five years after the S.G.C.'s inception. After that Chekov was supportive of the Stargate program operating within Cheyenne Mountain. He took command of Russia's own battle cruiser, the Korolev, and was killed when the ship was destroyed by Ori warships on its first mission.
The Tomb - Colonel Chekov and the Russian government are furious when all but one member of a Russian team are killed on a mission with SG-1.
48 Hours - Dr. Jackson and Major Davis must negotiate with Chekov for the Russian's DHD, in order to save Teal'c's life. He agrees to loan it to the S.G.C., but the device is accidentally destroyed.
Redemption, Part 1 - Appointed to be the Russian envoy to the S.G.C., Chekov insists that a Russian be appointed to SG-1 to replace Daniel Jackson. He is furious to learn (again) that the S.G.C. has withheld technology from them.
Redemption, Part 2 - Chekov negotiates to sell the Russian Stargate to the S.G.C. when their gate is destroyed by Anubis -- and, apparently, to have a Russian team stationed at the S.G.C.
Disclosure - Chekov joins General Hammond and Major Davis in informing the British, French and Chinese governments about the Stargate program, and helps to convince them that it is to their advantage to allow the U.S. to operate the gate.
Full Alert - Colonel Chekov arrives in the United States in the hopes of averting a war between the US, Russia and the Goa'uld hiding in-between.
The Fourth Horseman, Part 1 - Chekov joins the representatives of the International Committee at Stargate Command as they try to resolve panic surrounding the Prior plague that is sweeping the planet.
The Fourth Horseman, Part 2 - Colonel Chekov and other international representatives interrogate General Landry over his command decisions after Earth is stricken by the Prior plague.
Crusade - Chekov threatens to rescind the U.S.'s rental of the Stargate as part of a gambit to obtain the next Daedalus-class battle cruiser for his country.
Camelot - Chekov takes command of the new Russian battle cruiser Korolev to join the stand against the invading Ori fleet at the Supergate.
Flesh and Blood - Colonel Chekov perishes when the Korolev is destroyed by the Ori.