Brian is a talking dog, who has lived with the Griffin family since Peter picked him up as a stray.

While he exhibits some typical dog behaviors like eating garbage, licking himself, playing fetch, leaving dead birds on the porch, intensely fearing the vacuum cleaner and the dog whistle, toilet flushing, and sleeping at the foot of Peter Griffin's bed, barking uncontrollably at other dogs, and trouble standing up in the car.

He also possesses various anthropomorphic qualities, such as the ability to speak intelligently, drive a car, and walk bipedally. He also has a particularly sharp wit. Peter is his best friend, despite Brian's vastly superior intelligence.

While not seen holding a regular job in Quahog, Brian is depicted owning a car, paying bills, and maintaining a credit card. In various episodes he has been a substitute teacher at Chris' school, a contributor for the The New Yorker, a taxi driver and a drug-sniffing dog for the Quahog police department. He also worked selling cars, Brian held several jobs while living in Los Angeles including waiter, car wash attendant, screenwriter and pornographic film director.

Brian was born on a farm in Austin, Texas, in a litter of five puppies, of which he was the only anthropomorphic. His youth and adolescence have not been explored in detail, though it is assumed that at some point in this time he made his way to Rhode Island. He was homeless, panhandling, and cleaning windows on the side of a highway exit when Peter found him. Although he had no money to give Brian, Peter felt bad for him, so he brought Brian into the Griffin's house and family. Brian also intermittently attended Brown University, though he remains one class short of graduating

When Brian returned to Austin to find his mother, he found that she had died and her owners were using her stuffed body as a table. Brian absconded with her body to give his mother a proper burial.

Prior to Brian, the Griffins had another talking dog named Todd, who is thought to have been put down at the age of 15 due to illness.

Despite his anthropomorphic intelligence, Brian shares certain traits and shortcomings with real dogs. For example, he cleans himself with his tongue and scratches at fleas with his hind leg.

Furthermore, although his maturity and broad range of experiences seem to imply that he is as old as a middle aged human, as a dog, he is only seven years old. Peter has been known to tease him about his shorter lifespan.

Brian is prone to alcoholism (which isn't helped by the fact that he seems to have a very low tolerance for alcohol), and in one episode gets treatment for cocaine addiction after becoming a detection dog. He has also referred to buying, being in possession of, or smoking marijuana.

Brian has a cultured background; he loves opera and jazz, and loves to sing. He is depicted speaking fluent French, Tagalog, and decent Spanish. He is also a member of Mensa, and is an avid writer

Brian seems somewhat ashamed of his animal urges and insecure about his canine status in general. He once refused to do degrading pet tricks for Peter during a dog show, despite it being necessary to win the money needed to buy the family a new air conditioner. He also chastised Lady and the Tramp for acting in typical dog-like behavior, saying, "That's just what they want you to do".

He suffers mistreatment as a dog, with references to movies like The Autobiography of Miss Jane Pittman and School Ties, movies about characters who suffer from racial segregation and anti-Semitism. He is humiliated when the Griffins catch him with canine pornography.

Brian is apparently working on a novel, but the fact that he just can't seem to finish it has become a running gag.

Peanut butter jelly time.