Siobhan grew up in a wealthy household with loving parents, Moira and Dominic, and a younger sister Morgan. She has created the most popular club in Windenburg, the Paragons, and as its leader she is one of the most looked up to Sims in the city. Siobhan is in a relationship with one of the club members, Sergio Romeo. She has established a popular network of friends in order to rise in the business career. She works as an Office Assistant and enjoys fashion, fun, and drinking at cafes. However, being a Paragon means being in constant war with their rival group, the Renegades, to which her sister belongs. This makes her mother worried, as the sisters no longer get along because of the rivalry.
Siobhan, like her mother, has an Irish name with a very particular pronunciation. "Siobhan" is pronounced as "shiv-awn.", possibly hinting that she may be of Irish origin.