Father, Angus O'Shea, proprietor of the O'Shea Tavern.
Mother, Anne O'Shea, deceased.
Brother, Connor O'Shea, tavern manager.
Aunt, Commander Helen O'Shea, Star Fleet Intelligence.
Cousin, Lt. Commander Shiro O'Shea, Professor of Engineering, Starfleet Academy.

A former tavern manager, Sean still enjoys tending bar for his friends and is an avid dart player. He also enjoys exotic cooking and tries to get samples of local spices and seasoning from each new culture he visits. Sean competed during his collegiate days in fencing and still attempts to keep his skills honed.

Sean was the oldest son of Angus and Anne O'Shea, and as such, was first in line to inherit the tavern that had been in his family for generations. Growing up in Cork, Ireland, he rarely thought about life beyond the boundaries of his hometown. He seemed perfectly content to follow in his father's footsteps, becoming a bartender and tavern manager as soon as he was old enough to handle the responsibility.

Sean's mother contracted terminal cancer when he was in his late teens. Sitting at her bedside during her final hours, Sean was shocked to hear his mother's dying revelation. She had once been accepted to Starfleet, but had been talked out of it by her family, who wanted her to settle down and stay put. She pleaded with her son to seek more out of life, and not to settle for the confines of the tavern. Sean promised that he would carry out his mother's dying wish.

Success did not come overnight. Sean realized that before he could aim for the stars, he needed to build a strong foundation. He applied for and was accepted into Oxford on a scholarship, where he spent six years earning advanced degrees in medicine and xeno-biology. Helping people came naturally to Sean as did the desire to constantly improve and expand his skills.

Already a talented doctor and researcher upon application, he was quickly accepted into Starfleet Academy, where he breezed through his four years and moved directly onto Starfleet Medical. He applied himself to learning everything he could about the many species that made up the Federation and the galaxy in which he lived. His talents attracted the attention of Starfleet's Advanced Xeno-Biology Institute. He was offered a position as a researcher, but declined initially, feeling that in the midst of war, there were more important places for his skills.

Sean found what he was looking for on Bajor. He arrived shortly after the Dominion and Cardassian occupation forces withdrew, leaving destruction and suffering in their wake. He spent three years working as a general practitioner, doing his best to heal the wounds of war. He fell in love with the planet and its people and felt he was truly making a difference. After three years, he was ready to try something new and challenging. The Advanced Xeno-Biology Institute had left him an open invitation and Sean decided it was finally time to accept.

The institute turned out to be one of the darker times in Sean's life. While a great deal of legitimate research was performed, the Institute also served as a tool for Starfleet Special Operations. Sean was called upon to "study" the effects of various weapons, diseases and psychological inducements on species that were hostile to the Federation. The research was a closely guarded secret, one that could have had grave repercussions had word ever spread to the general population. Two years at the institute was all that Sean could handle. He felt as if he had mortgaged his soul. His resignation came in the form of his fist cracking against the institute founder's jaw.

While emotionally satisfying, Sean's fiery resignation did not come without a price. Sean found himself bounced out of active Starfleet duty. He drifted for a while, getting himself in trouble in more than one port of call. He was arrested in the Rigel system by Starfleet but all charges against him were mysteriously dropped. With no where better to go, Sean returned home with the intention of running the family business again. But Starfleet threw him a curve ball, giving him a choice assignment as CMO on the newly commissioned USS Sulu. Sean has no idea to whom he owes his good fortune, but he is not complaining. He looks forward to putting his past behind him and getting back to doing the work he was trained for.

Sean is usually even tempered and easy going, at least professionally. His years as a bartender have taught him to accept new people at face value and he tends to make friends quickly. But at the same time taught him how to brawl with the best of them when diplomacy fails. His career has forced him to witness a great deal of physical and mental suffering over the years and he is quick to sidestep how that has affected him. He tries to live his life completely free of regret, making decisions and standing by them. He is not afraid to admit when he is wrong or needs help, and respects others who act the same. He has been through a number of minor romances that never seemed to evolve into serious relationships. Sean is a hard worker and plays hard as well. Out of uniform, and on shore leave, he has no qualms about cutting loose, getting in trouble and working out the consequences later.