Brian Griffin is an 8-year old talking white Labrador who has lived with the Griffin family since Peter picked him up as a stray. He also possesses various anthropomorphic qualities, such as the ability to speak intelligently, drive a car, and walk bipedally. Earlier in the series, he used the catch phrase "Whose leg do you have to hump to get a dry martini around here?". He also has a particularly sharp wit. Peter is his best friend, despite Brian's vastly superior intelligence - on several occasions, Brian has had to explain Peter's inability to do various things, such as haggling over prices. In "Brian Goes Back to College", it is revealed that Brian went to Brown University in Rhode Island, but did not graduate.
Brian has a cultured background; he loves opera and jazz, and is a fan of John Coltrane. Brian speaks fluent French and Tagalog, and is competent in Spanish. He is also a member of MENSA. He loves to sing and can imitate a barbershop quartet without accompaniment. He is also an avid writer, having once been invited to write for The New Yorker, although he was fired once the magazine learned he did not graduate from college. He has also written a novel, although has made little progress other than the title Faster Than the Speed of Love, and a synopsis similar to the film "Iron Eagle III", for which Stewie and Lois mock him, and this subject has since been brought up several times throughout the series. He is a smoker, an alcoholic and recovered cocaine addict. Brian discovered that his cocaine habit stemmed from his mother abandoning him for which he saw a therapist. He has also made references to either buying, being in possession of, or smoking marijuana in numerous episodes. In "420", he actually does a whole dance to the song A Bag of Weed. In "It Takes a Village Idiot, and I Married One", it is revealed he has a Ziggy tattoo. It is shown in "Brian & Stewie" that he keeps a gun just in case he wants to commit suicide.
In "Stewie Griffin: The Untold Story", Stewie traveled to a future where he learned that Brian died. Brian is seen in heaven at a table drinking martinis with Vincent van Gogh, Kurt Cobain, and Ernest Hemingway. They then all say that they killed themselves out of passion for various reasons. He then admits that he ate some chocolate out of the trash can.
A list of Girls Brian has been with:
- Cheryl Tiegs
- Holley (Road to Multiverse)
- Jillian Russell-Wilcox
- Lauren Conrad
- Lois Griffin
- Meg Griffin
- Brian once dated a neglectful preschool teacher known as Miss Emily and looked past the neglect of the children (including Stewie) to continue being with her. He only reports her after he learns she has another boyfriend. This is considered his Moral Event Horizon by some, as he turns her in to the authorities.
- In Killer Queen, Brian tormented Stewie with a Queen album's creepy imagery, almost driving Stewie to commit suicide over the trauma. He then discourages Stewie into showing it is just an album cover.
- Once, he shot an innocent man and said to him, "Later, Dink."
- In The Thin White Line, Brian became addicted to cocaine. This led to some uncomfortable turbulence as he became more aggressive with his family.
- Brian is in love with Lois Griffin, constantly flirts with her, and, in Play It Again, Brian, tries to show it by nearly raping her.
- In another instance, Brian dates a blind woman and tries to hide the fact that he is a dog. When exposed, she breaks up with him for the lie. However, he is shown at the end of the episode taking advantage of her blindness by pretending he's another guy with a different voice with the implication that he will trick her into having sex with him.
- In a cutaway gag, Brian accidentally runs over Dean Koontz and backs over him again once he found out he wasn't Stephen King.
- Brian steals the Golden Clam Trophy due a fondness for shiny things, which causes great tension between the residents of Spooner Street (which led to accusations of theft), and sway them from learning the truth. He also presumably killed Rod Serling in a cutaway gag following this incident.
- When Brian got a gag self help book called "Wish it, Want it, Do it" published, he became extremely selfish, ungrateful, and arrogant when the book became a success. Even though Stewie had helped him get the book published in the first place and had offered to be his publicist, Brian abused him many times. Such examples of this abuse included forcing him to return to their hotel alone just because they had eaten dinner in the back room of a fancy restaurant, blaming him because Brian was standing under an air vent, and firing him for forgetting to tell him about a change in a talk show. At the end, Brian still blames him for his own mistakes on said show.
- Brian is also shown to have a nasty habit of being unreliable with paying up, such as with his bet with Stewie and setting up his date Ida to pay for drinks after promising he would cover it (although the former led to one of Stewie's more villainous moments when he tortured Brian multiple times over the bet).
- When Stewie offered Brian one free punch, Brian used this to terrify Stewie, to the point where he beats himself up. In the end, Brian kicks Stewie into a double-decker bus. However, considering Stewie viciously beat him up twice, shot him in both knees, and torched him with a flamethrower in the same episode, they would be considered even.
- During their attempt at doing Santa's job in Road to the North Pole, Brian and Stewie murder a little girl's parents to prevent them from calling the cops.
- Despite having good intentions in that he was trying to convince Mayor Adam West to revoke the gay marriage ban, Brian still held the mayor hostage at gunpoint.
- While hanging out with Frank Sinatra Jr., he decided to live life at the fullest. But as a result, he became an alcoholic, abandoned Stewie, where he was attacked by man-eating deer and lost an ear, and even bit Peter.
- In Stewie B. Goode, Brian gave Stewie alcohol and made him drunk, although it was originally to teach him a lesson.
- In the same episode, Brian brought Stewie to the Drunken Clam, which is illegal to bring children to bars. Both Brian and Stewie drank so many martinis that they ended up crashing into the Drunken Clam, causing property damage, and, unintentionally, made Peter lose his job in You Know What Grinds My Gears?.
- In the video game Back to the Multiverse, Brian is shown freely engaging in attacking, killing, and other atrocious acts, including a disgusting sense of "humor" when he ignores Joe's calls for help after the boss fight against Crippletron. He even assassinates Mayor MacCheese on behalf of "Evil Mayor West" in order to retain a favor in one dimension, and is really only concerned about Evil Mayor West backing out on his deal; although in fairness, Brian is trying to keep Evil Mayor West from providing weapons forBertram's plot. He also has an odd Even Evil Has Standards moment when he considers Stewie "sick" for killing the Santa Claus of one dimension by dropping a TV set on him.
- Brian has shown to be a hypocrite from time to time:
- A second example is in Brian & Stewie, in which despite being liberal, he keeps a pistol because of protective reasons and pretends to be against using a gun itself over the "national tragedy at Combine".
- Another example of Brian being a hypocrite is when he deliberately runs over a squirrel, which, unbeknownst to him, traumatizes Stewie. He also hires a hitman to kill Quagmire's cat. Also during a date in Love, Blactually, he mauls a rabbit at a pet store. These actions make him a hypocrite because in several episodes he supported animals rights and was against violence towards animals.
- And the last example is his views on LGBT rights, which he violated in Family Gay when Lois is depressed that Peter is leaving her for another man, Brian then takes Stewie's idea for ending Lois's depression by kidnapping Peter and taking him to an ex-gay center to "turn back to his old self".
- In Brian's a Bad Father, Brian has neglected to visit his human son Dylan. But upon hearing he is a famous TV star, Brian sets to become a writer on his show. Dylan realizes Brian only took the job for his own advantage and pointed out what a bad parent he really is. Brian also steals a table of food from the studio. Fortunately, they make up later on thanks to Stewie.
- In Herpe the Love Sore, he gives Stewie and Chris herpes by transmitting blood, knowing very well that he himself has the incurable disease and kept it a secret from them. The two exact revenge on Brian as a result.
- In Brian the Closer, Brian gets a job as a real estate agent after undergoing surgery. He cons Quagmireinto buying a run-down apartment loft, despite the fact that he consoled and helped Brian earlier in the episode. Later Brian apparently comes to the realization of his actions and admits what he did was selfish and pretentious - until revealing it was part of his devious plan.
- In Stewie, Chris, & Brian's Excellent Adventure, Brian ends up telling Chris that he built the time machine, thus taking credit for Stewie's work. Brian also ends up taking a detour on their time travel tour to go see Ivan Pavlov, a man who experimented on dogs and he ends up beating him to death.
- In This Little Piggy, while Brian and Stewie are at the Folk Festival, they both meet a hippie girl who ends up overdosing on cocaine. Afterwards, Brian and Stewie both decide to dump her body in a pile of other dead hippies, Brian feels nothing over dumping her body or seeing the other corpses. Stewie regarded him as a monster for his sexual objectification of the hippie girl and knowing nothing about her.
- In the episode Stewie is Enceinte, Stewie decides to impregnate himself with Brian's seed, in the hopes of having his babies so that they can grow closer. Brian constantly tries to kill the unborn babies by pushing Stewie down the stairs or through other various evil acts. When the babies do finally come, he ends up getting closer to them, but once they clear up a misunderstanding, Brian suggests they get rid of them, by giving them to a pet shelter.
Family Guy: Brian's explanation of why he's washing the sheets (that he soiled).
- Lois: Those look like our sheets and our quilt.
- Brian: They are — I'm-I'm washing them in some fabric softener because last night they were so itchy I couldn't sleep which is why I was downstairs when you asked me if everything was okay... You know, 'cause it was so itchy.