Jacob Carter, father of Samantha Carter and her brother Mark, had served in the US Air Force with his friend George Hammond during the Cold War. When Sam was a teenager, Colonel Jacob Carter had been delayed when picking up his wife after an appointment. She had taken a cab instead and was killed in a tragic auto accident. Jacob's son, Mark, blamed his father for the accident, which led to their estrangement for many years. A proud man, Jacob tried to reconcile with his daughter, but his relationship with Sam remained strained.
Years later, Jacob was approaching retirement as a major general when he was diagnosed with lymphoma. He was reunited with his daughter at an Air Force function in Washington, DC where Sam was to be awarded the Air Medal for heroism, but their reunion was an awkward one. As a final gift for his daughter he had pulled some strings that would make it possible for Sam to enter the space program at NASA and fulfill her childhood dream, but because of the classified nature of the SGC, Sam couldn't explain why she must decline his offer.
Jacob's cancer spread quickly to his liver and he was admitted to the US Air Force Academy Hospital where he was expected to live only days. It was then that he learned about the Stargate Program and his daughter's true career. SG-1's recent contact with the Tok'ra had presented an opportunity, and Jacob agreed to become a host to Selmak, a wise and respected leader among the Tok'ra. The symbiote cured his cancer, as well as his arthritis, and as a Tok'ra with a true symbiotic relationship, Jacob gained the knowledge of the Tok'ra, including the ability to speak and read Goa'uld, to use Tok'ra technology, and to pilot both a cargo ship and a mothership. He did, however, give up coffee, a taste for which Selmak did not share. At Selmak's urging, Jacob eventually visited his son Mark and the two reconciled, and his relationship with his daughter became stronger than ever.
Jacob remained in frequent contact with the SGC and acted as a liaison between the Tok'ra and Earth. He provided invaluable assistance to SG-1 in fighting the Goa'uld, and in turn received assistance from them. When he was captured by Sokar and tortured on the prison moon of Netu, the Tok'ra and SG-1 mounted a joint rescue mission. Jacob also joined SG-1 on numerous missions. He assisted in the battle against the Reetou rebels and took young Charlie back to the Tok'ra to save his life, he sought SG-1's help in finding and eliminating Seth on Earth, he joined the rescue mission when O'Neill and Teal'c were stranded in deep space during the failed test flight of the X-301, he orchestrated the mission to sabotage the alliance between Apophis and Heru'ur, he joined SG-1 in defeating Apophis and the Replicators in a captured mothership, he participated in the sabotage of the summit of System Lords in the Hassara System, he joined the mission to salvage Anubis's abandoned ship from Earth's orbit, and he acted as a leader among the refugee Tok'ra at the Alpha Site. He has offered access to Tok'ra technology and knowledge, sharing TERs to prevent a Reetou invasion of the base, attempting to use the healing device to heal Daniel after his lethal exposure to radiation, offering refined tretonin as a means to cure Teal'c and Bra'tac after the loss of their symbiotes, and proposing cryogenic stasis as a means of maintaining the life of the young cloned O'Neill until a way could be found to reverse the cellular breakdown that would eventually kill him. He has also cooperated with the SGC in developing new technologies. He participated in the testing and interrogation of the captured Kull Warrior, and joined the SG-1 mission to Tartarus to infiltrate Anubis's base in order to find a way to defeat his drone army. Using the analysis of the genetically engineered drone soldiers and Telchak's reanimation device, Jacob and Sam collaborated to develop a prototype energy weapon that would neutralize Anubis's Kull Warriors.
Despite Selmak's position on the Tok'ra High Council, Jacob's close ties to Earth caused other Council members to begin to doubt Selmak's true loyalties and to question Jacob's sympathies toward the humans of Earth. With increasing frequency, the Council began to meet and make decisions without informing him, and Jacob's attempts to maintain ties with both Earth and the Rebel Jaffa were hampered as his support within the High Council diminished. As the alliance among the Tok'ra, Rebel Jaffa, and Tauri crumbled, Jacob chose to stay with the Tok'ra in the hope of rebuilding the alliance.
For nearly a year, Jacob remained largely out of touch, and although his relationship with the High Council remained strained, he returned to the SGC when the Replicators entered the galaxy and launched a full scale war against the Goa'uld. He offered his advice to O'Neill and shared Tok'ra technology, stolen without the knowledge of the Council, to monitor the progress of the battle. He also collaborated with Sam to decipher the Ancient writings on the monument of Dakara, and to modify the Ancient device with which the Replicators were finally defeated.
For several weeks before the mission to Dakara, Selmak's health had been growing steadily weaker. As one of the oldest among the Tok'ra, Selmak had lived 2000 years and had reached the age of natural death. A certain amount of energy and a conscious effort is required for a dying symbiote to prevent the release of toxins that would kill the host, and although Selmak chose to spare Jacob's life, Jacob insisted that Selmak was vital to the mission on Dakara, and he refused to let him go. Selmak's knowledge of the Ancient language and technology proved invaluable in modifying the device on Dakara as an effective weapon against the Replicators, and Selmak held on as long as he could, but he slipped into a coma immediately after the weapon was activated, no longer able to block the toxins that would kill his host.
Jacob kept his condition a secret from his daughter as long as he could, and he made the acquaintance of Sam's fiancé, Pete Shanahan, as she prepared for her wedding. As his health deteriorated, however, he was forced to admit the truth to Sam, and he urged his daughter to make the choices that would bring her happiness. After years of estrangement, Jacob and his daughter had been closer in the six years since he had become a Tok'ra than in her whole life before, and after bidding a gentle goodbye, Selmak and Jacob quietly passed away.
Portrayed by: Carmen Argenziano
Episode Reference: Secrets, The Tok'ra, Show and Tell, Seth, Jolinar's Memories, The Devil You Know, Tangent, The Serpent's Venom, Exodus, Enemies, Summit, Last Stand, Meridian, Descent, Allegiance, The Changeling, Fragile Balance, Evolution, Grace, Death Knell, Reckoning, Threads