Brian was created by screenwriter Gary Scott Thompson, who was inspired by an article on street racing that was published in the May 1998 issue of Vibe magazine.

O'Conner, under the alias Brian Earl Spilner, first interacts with Dominic as an undercover police officer tasked with bringing him to the law.

These events help build many of his attributes: often the second in command to Dominic, Brian is shown to be honorable, honest, and protective, especially in regards to his family and wife, Mia Toretto.

He won the 2002 and 2014 MTV Movie Awards for Best On-Screen Team with Vin Diesel for his performances, and Walker became strongly identified with the character, with Brian being widely considered among the primary reasons of the longevity of the series.

He remembers little of his father and is close childhood friends with Roman Pearce; attending the same high school, the pair also dated the same women.

He joined the Los Angeles Police Department (LAPD), and two months into his tenure on the force, Roman was arrested for housing stolen cars in a garage.

During the events of the first film, Brian is working as an undercover detective with the LAPD, who assigns him the task of solving a series of semi-trailer truck hijackings.

He is given a very short amount of time to find the people responsible before the truckers start arming themselves with shotguns and taking matters into their own hands.

While running with Dom, he proceeds to investigate rival race crews led by Johnny Tran (played by Rick Yune) and Hector (Noel Gugliemi).

Brian soon finds out Toretto is responsible after watching him suddenly leave in the middle of a party at Race Wars and seeing Mia weeping to herself.

He then reveals himself to Mia as a police officer and convinces her that if he does not get to her brother and his crew fast, they could get seriously injured or killed by the truckers who have begun to carry firearms.

While the FBI launch a national manhunt for him, Brian travels across Arizona, New Mexico, and Texas, winning every street race he participates in, with his red Dodge Stealth.

Brian, now living in Miami, Florida competes part time as a street racer for his friend Tej Parker (Ludacris).

However, US Customs Agent Markham (James Remar) later gives him an offer to work undercover to infiltrate a local drug kingpin named Carter Verone (Cole Hauser) in exchange for a clean record.

After the agreement is settled, Bilkins and Markham then introduce Brian and Roman to Monica Fuentes (Eva Mendes), an undercover US Customs agent working with Carter.

He and Monica exchange a meaningful glance, and the end scene is shown between O'Conner and Pearce walking away with their pockets full of Verone's drug money planning to open up a high-performance garage.

Brian O'Conner, now a fully reinstated FBI Agent, is given the task of bringing down Arturo Braga, a known drug trafficker in Los Angeles and his connections to the street racing world, although his real identity is unknown to the public.

Brian is also not surprised to see Dominic Toretto doing a Suge Knight style balcony interrogation of possible lead David Park.

Also, it was Brian who was contacted by Letty with her proposal to infiltrate Braga's organization in exchange for Dom's safe return to Los Angeles.

This leads Brian to resign from the FBI, and he joins Mia and two of Dom's Latino accomplices from the beginning of the film (Leo and Santos, played by Don Omar and Tego Calderón respectively) in freeing Dom from his prison bus by driving towards the bus in similar style to Dominic's heists, which later leads to Dominic's appearance in Tokyo, Japan during the end film events of The Fast and the Furious: Tokyo Drift.

During the conversation they share, she reveals her anger at his "betrayal" of their group at the end of the first film, questions why he let Dom go (to which Brian claims he doesn't know) and tells him how hurt she was when he left her suddenly, with no explanation.

O'Conner joins Toretto's team in complying with the request of Agent Hobbs to take down rival gang leader Owen Shaw.

After successfully questioning Braga and returning to London, O'Conner starts to feel guilty for letting Letty go undercover, which led to her amnesia and subsequent work for Shaw.

After the ambush, Nobody's men are killed and Nobody is injured, though he manages to escape with Toretto and Brian, while Jakande obtains God's Eye.

Just as they are preparing, Brian calls Mia and professes his love, fearing he may not survive, and learns that she is pregnant with a baby girl, motivating him to come back alive.

In the aftermath, Hobbs kills Jakande by shooting the bag of grenades that Dom managed to throw inside the helicopter, while also taking out the UAV.

The film concludes with Brian arriving at Dom's house in his blue Nissan Skyline to join the rest of the team in a post-mission barbecue, although he is not featured directly.

Despite his composure, Brian is a secret adrenaline junkie; once, he confides in Dom (when describing the challenges of fatherhood) that he misses the dangerous lifestyle.

Brian was first unknown with the car tuning community, but after with meeting Toretto, he became more positive, active in the racing scene, becoming a skilled mechanic.