Derrick was born in Cork, Ireland and spent the first three years of his life on the family farm. His parents separated when he turned three, and he moved with his mother and sister to New York City, while his father moved to San Andreas. Derrick had a normal childhood and lived in N.Y.C for 11 years where he was homeschooled with his sister by their mother. His three-years-older-sister Jenny taught him everything she could, from how to read, to how to ride horses and motorcycles, to how to hold and shoot a gun. At the age of 14, Derrick's mother fell sick and was no longer able to care for her children, and so Derrick and Jenny ended up moving to San Andreas to live with their father on his farm in Grapeseed. It was around this time that Jenny began schooling that would lead to her joining the LSPD. Derrick kept busy with being home schooled while learning how to work the farm, finding flying the crop dusters to be the most exciting part of the job. He quickly learned how to fly the small planes, but on the ground grew bored and he found himself making his way down to the city of Los Santos any chance he got. Derrick found himself spending his time with a group of kids of the same age who spent most of their time on the streets of LS, and he quickly learned all of the things that his sister and his home schooling didn't teach. Derrick eventually left what he called the boring life of the farm in Grapeseed to stay with his friends in the city and he spent the next three years making a living committing petty crimes including selling weed and robbing small stores. Derrick had mastered talking his way out of situations and managed to stay out of jail for the entire time he spent with these friends. One of these friends, Cara Jackson, and Derrick began to spend all of their time together and it was now that he started drinking and using hard drugs. Sometime during this Cara and Derrick became engaged to be married. After three years, the crimes had become more dangerous and complex. On the warm summer morning of July 29th, near Chumash, both Derrick's fiance and sister were found dead - both had been shot multiple times. It was at this time that Derrick went into hiding for the next three years.

In the fall of 2021, Derrick found himself spending time with an old acquaintance - Oliver O'Brien. The two, along with three others (Jack Thomas (not the Jack that shows up in the wiki), Billy Bob Jr., and John Feltzer) formed a group called The Brotherhood. The group had their hands in every form of crime in the state. Derrick began drinking again, as well as abusing prescription pills, when the highs of the crimes they would commit would wear off. Four months after joining The Brotherhood, Derrick met a young woman named Petal which would change everything. Derrick left the group to focus on working on his own issues, to help Petal with hers, and because he felt he was a liability to the brothers and that his actions would bring them harm. He continues to work with professionals to address his addictions, and recently created and has been approved to open Third Eye Tea House.

Derrick knows close to nothing when it comes to pop culture. His friends at times think he is working with the police due to his ability to talk his way out of tough situations.