The son of two Starfleet Officers from Alpha Centauri, Sergei always knew he wanted to join Starfleet and explore the stars. He is proud of his Centauri heritage as one of the oldest colonies from Earth.

He joined the Academy and excelled in his studies, and was drawn to the study of Genetics and Biology.

He stayed for Medical School and completed his doctorate, and was assigned to the U.S.S. Carpathian.

During a border skirmish with the Cardassians, his away team was trapped on a planet. At this action, under heavy fire, he dragged a wounded comrade to safety and treated her wounds. He was awarded the Star Cross for his bravery.
However, his best friend since childhood, Artyom Limisov, was killed in action. Since then, he has hated Cardassians.

Later, aboard the U.S.S. Constantine, he participated in First Contact with the Ligrellans, creating convincing prosthetics to allow initial infiltration and analysis for First Contact.