Dallas P. Cassidy was born in Dallas, Texas the second of three kids. He grew up the son, grandson, and great-grandson of various Law Enforcement Officers. His great-great-grandfather was Robert Leroy Parker, better known by his criminal name: Butch Cassidy. Ever since his death, the family took up the other side of the crime to rectify their ancestor's actions. His parents moved from Houston to Dallas shortly before his birth. He would go on to grow up and go to school in the Dallas suburbs. There he was a three-sport athlete competing in Soccer, Basketball, and Baseball. Outside of sports, Dallas was always a social butterfly and could be found at various parties and social events. It was at such that Dallas met the first and arguably the most impactful of his girlfriends, Mia Morales, who he would continue to be with from high school until age 24.

After graduating High School, Dallas got a criminal justice degree from a local community college and joined the DPD where he worked for 3 years before joining the US Marshal service. For this job, he would be forced to travel across the country hunting some of the most dangerous criminals. This would play a huge factor in his life in many ways. He would only work for the Marshals for 3 years before moving to LS hoping to find some of normalcy and a true home.

Currently, Dallas Cassidy resides in northern Los Santos and works for the Blaine County Sherriff's Office. He can be found both in the morning "EU" hours as well as in the late night "NA" hours. When not at work, he is often found hiking, mountain biking, scuba diving or riding his motorcycle. He is an insatiable flirt who loves to hangout with people and make new friends. He sometimes struggles with all the things has seen and done in his past but often never brings it up not to burden anyone with his baggage. He will do whatever it takes to make sure the people around him are happy and taken care of. After working for the BCSO for several months, Dallas accepted a position as a detective which he continues to work as today.

Sgt. Duncan Murray: "Dallas, can we get back to work or would you like to flirt some more with the lovely medics"
Dallas: "I think I'll flirt some more, first, and then get back to work"
Murray: "...Fair enough"