A retired Starfleet chief petty officer who, with his wife Helena, adopted and raised the orphaned Klingon boy Worf on Earth.
Sergey Rozhenko is the human who took in Worf after the infant Klingon was found among the survivors of the Khitomer massacre. A veteran of Starfleet who served as a chief petty officer, he and his wife Helena raised Worf as their own son, first on the farm world Gault and later on Earth.
In Family, Sergey and Helena visit the Enterprise while it undergoes repairs at Earth after the battle with the Borg. Sergey is warm, talkative and eager to share stories of his son and his own Starfleet days, which embarrasses the reserved Worf. His visit helps show how deeply his parents accept Worf despite his discommendation.