S.T.A.R.S.

Jill Valentine is an American Special Operations Agent (SOA) of the Bioterrorism Security Assessment Alliance, of which she is a co-founder and an original member. She is a respected high-ranking operator, owing to her commitment in eradicating bioterrorism and her survival amid to the Biohazardous outbreaks in Arklay County in 1998.
In the early 1990s, Valentine served in the United States Army and got the attention of recruiters for Delta Force, the nation's primary counter-terrorism unit. Despite her sex, Valentine was allowed to take part in the six-month intensive Operator Training Course, where she excelled in bomb disposal and lock picking and was known for her delicate though precise work, resilience, courage, and discernment amid the danger. This experience made Valentine one of the only women in the world with Delta Force training.

Some time in 1996, Valentine was recruited by Albert Wesker for the Special Tactics and Rescue Service (S.T.A.R.S.), an elite unit of Raccoon Police Department (RPD) that relied on military veterans and weapons-trained scientists to solve serious crimes in Raccoon City, having only joined the unit due to their strong commitment to justice and desire to "experience the true feeling of life". Despite keeping her special forces training and personal life a secret, she made friends with several S.T.A.R.S. members during this time, including Chris Redfield, with whom she developed a close friendship and partnership, and under whom she often trained in marksmanship, and Forest Speyer who she already had a close friendship, and knew before S.T.A.R.S. thanks in part to both having served in the United States Army. By July 1998, Valentine became the only woman to join Captain Wesker's Alpha Team, as the team's B&E specialist, positioned at the rear in maneuvers with S.T.A.R.S. helicopter pilot Brad Vickers.