Sydney was born and raised in Hawaii. She now works out of Trinity College in America, where she both lectures and is available for contact about the authentication and retrieval of ancient relics from all over the world.
Her father is shown as involved in working on the engineering of dams, and he has a young american fiancee who he met when she was working as his interpreter in China. Sydney's asian mother, his first wife, is deceased.
Sydney works closely with Nigel Bailey. Nigel speaks with an unusual English accent and does Sydney's bidding usually without question. His knowledge rivals her in some areas of history, though their own specialties are not set out definitively. Nigel and Sydney's relationship remains undefined through most of the series. Though he is clearly her right-hand man both professionally and otherwise, their sexual and emotional tension is only generally explored through misunderstandings, misdirection, and the occasional disguise-by-way-of-kiss. Sydney and Nigel both persue relationships with other characters, though most of these liasons last only the episode in which they begin. Nigel's relationship with Interpol agent Cate went wrong partly due to her uneasiness with the state of Nigel and Sydney's affection. Nigel seems far more willing to explore where their interactions might be heading; Sydney routinely avoids the issue by teasing him and talking around whatever touch or situation they may have recently shared. She has no problem with appearing in repeated states of undress before him.
Sydney's sexual relations with other male characters are usually shown as being extremely passionate. She admits being aroused by the dangers of her profession, and other relic hunters or adventurers she shares quests with often end up as her bedmate or prospective lover due to this. It is also common for their subsequent meetings to be confrontational. Sydney has been stalked by one such ex, a lover who she met again in episode fifteen Affaire De Coeur, according to the thirty-fourth clip-show episode.
Sydney is proficient in both hand-to-hand (seen in most episodes) and weapons (seen in particular in episode thirty, Roman Holiday) combat. She has a great many contacts all over the world, in the archaeological fields and otherwise.
Sydney is very protective of both her assistants, and her students and colleagues. She is willing to fly to any country at no notice to fetch back, "save" or avenge them, as seen for example again in Roman Holiday, episode 24 Dagger of Death and episode 28, Gypsy Jigsaw.