- This character is a member of Spock's family.
Tremontaine was a vegetarian, and wore her hair in a variety of lengths, styles and colors. Spock considered her to be decisive, self-confident, and composed. She bore a resemblance to Droxine from Stratos.
She was born in the city of Montréal, Québec, Earth, in an area known as Plateau Mont-Royal. She grew up in Québec with her parents and sister. As a child she hoped to become a concert violinist. She took classes in T'Paal at the Diplomatic Institute on Vulcan.
Prior to the 2290s, Tremontaine had built up an impressive career over more than twenty-five years as a mediator and an ambassador. Among her many achievements was ending the long war on Epsilon Canaris III, convincing the Gorn Hegemony to establish a long-term ceasefire with the Federation, and establishing programs on many non-aligned planets that allowed medical aid to be supplied. She had visited Vulcan and met Sarek a few times, though they had never worked together.
In 2293, Tremontaine completed dealings with Medusans and then traveled from Earth to Orelte to aid Spock in negotiating rubindium mining rights with the Frunalian ambassador, Jalira Tren. Upon her arrival at the meetings twenty-seven minutes late, she decided to announce that the Federation were ready to pull-out of the negotiations. While Spock didn't agree with her outright lie, the ends did justify the means as several days later Tren agreed to the terms that had been laid out.
Following the completion of the negotiations on Orelte, Tremontaine traveled to Marcos XII for an unspecified diplomatic occasion. Following the completion of this mission, she traveled to Alonis to aid Spock in his negotiations with the Alonis on the placement of a starbase on the planet.
She and Spock became romantically involved and shared a mental bond. But during their time on Alonis, James T. Kirk was reportedly killed while aboard the USS Enterprise-B, and Spock found himself too emotionally compromised to continue the negotiations. Tremontaine arranged transport for Spock to return to Earth to attend Kirk's memorial service. Afterward, Spock resigned his ambassadorship. During a ten-day gap in the Alonis negotiations, Tremontaine visited Spock on Earth. He explained his goal to recommence kolinahr training and shed his emotions, ending their relationship.
In 2312, Leonard McCoy visited Tremontaine at the Federation Embassy on Tzenketh to tell her that Spock had rejected his kohlinahr training and accepted having emotions. McCoy broke a promise by telling her that Spock still loved her. She immediately traveled to Rigel IV to be with Spock, and they rekindled their relationship.
- The Spock-Saavik marriage implied that Spock's marriage with Tremontaine had ended prior to 2329, either by annulment, divorce or possibly her death.