Alvin Seville is one of The Chipmunks and the overall main protagonist of the series and movies. He is the ringleader of the iconic trio. Alvin greatly relishes his role as band front man, and his impulsive behavior regularly gets him and his brothers (sometimes Dave) into trouble.
Alvin, the shortest of the Chipmunk brothers, is always scheming, whether it be because he wants to get out of chores (Overworked Alvin) or is just trying to find a place to relax (Alvin's Cruise). Alvin has much musical talent through singing and playing of his harmonica. He loves his harmonica and will play it any time he can, even if it ends up messing up the song ("Alvin's Harmonica"). Alvin has trouble grasping other languages or their cultures but enjoys traveling the world anyway ("I Wish I Could Speak French", "Comin' Thru' the Rye").
He can be lazy when it comes to working, but he can be very imaginative at times (Sir Alvin). He doesn't take lightly to people insulting him and his brothers' music (Squares), and sometimes even resorts to violence when dealing with people he dislikes (Daisy Belle in "Three Blind Mice"). He will also manipulate people when his fame is at stake (Disc Jockey). At times, the selfish side of Alvin can take over, but, in the end, he always returns to help his brothers and Dave (Alvin's Alter-Ego).
Alvin's interest in female characters isn't as strong as in later incarnations, but he definitely is a charmer ("August Dear").
Alvin is the oldest chipmunk, as revealed in the episode Grounded Chipmunk after making the statement, "I've never been alone, except those five minutes before Simon was born."
Alvin is charming, musical (able to play the guitar, piano, and harmonica, among others), and headstrong. He always seems to make up crazy plans to accomplish a goal, whether it is trying to help his brothers, preventing Dave from figuring something out, or getting out of a sticky situation. He is an emotional roller coaster ride and can have mood swings. Additionally he can be hesitant at first in some situations, but once he understands the circumstances, things are fine for him, like in the 1985 special A Chipmunk Reunion for example when Alvin has a hard time forgiving his mother for leaving them until he understands the situation.
Alvin is commonly portrayed as the charming one of the three. In the episode Dr. Simon and Mr. Heartthrob, he dresses stylishly and attempts to attract a group of visiting girls before being usurped by Simon, who drank a special kind of potion which granted him natural magnetism and charm.
Alvin can be impulsive which people, especially Dave, find bothersome. At times, Alvin's determination can be viewed as nuts. As a result of his constant habit of reacting to opportunity, Alvin has gotten his brothers or himself in trouble at times such as the balloon race in The Chipmunk Adventure and a large number of episodes.
Despite all of this, Alvin's intentions are good, as well as crazy and chaotic. He can be friendly at times. For instance in the 1981 special called, A Chipmunk Christmas, he gave his golden harmonica, one of his most prized possessions, to a child with a terminal illness. In Alvin and the Chipmunks Meet the Wolfman, Alvin helped Theodore temporarily get a bully off his case, making the principal remark, "I'll say this for Alvin: He sticks up for his little brother."
Alvin retains some of the traits he possessed from the 80s, such as his desire for fun, and charm as seen in Alvin and the Chipmunks: The Squeakquel where he manages to capture the attention of a group of girls using his cute looks and as well as the French language (e.g. he called BeccaMademoiselle after kissing her finger). Nevertheless, he has difficulty at showing affection toward Dave such as in the first film, Alvin and the Chipmunks, where he struggles at telling Dave that he loves him as a father, but less so with his brothers such as the time Alvin tried to kiss Simon to cheer him up in the second film. In the third film, when all of the Chipmunks are stranded on the island, Alvin slowly becomes the mature one, as seen when he yells at Simon (who had a change in personality due to getting bitten by a spider), only for Brittany to tell him he's starting to sound like Dave - much to his horror ("Nooooooooo!") and builds the boys' treehouse by himself.
Alvin is similar to his 1983 incarnation with some differences. He has a big hatred of school but is a skilled gamer. Additionally he has gotten into this habit of giving attitude, sulking, even whining when feeling upset or to get his way. He continues to flirt with women such as Principal Meadows (Principal Interest) or have crushes and/or idolizations on famous individuals (Mister Manners). He sometimes uses others, such as his brother Theodore, to do his dirty work. Though he acts out, he is very remorseful and does what it takes to make up (To Serve And Protect). He's still protective of his brothers (Bully For You) and has familiar emotional attachment at times (Warbie). Alvin retains his sporty lifestyle, frequently seen on his skateboard (What A Gem), though he tends to go too far when others are concerned (Mutiny).
Alvin's signature appearance has changed over the years. Before The Alvin Show, Alvin looked like a normal chipmunk somewhat similar to his CGI films appearance. Alvin wears just a red shirt with the letter 'A'. After The Alvin Show was created, Alvin was given more human features. He wears red shirt with his signature yellow 'A' that goes down to his ankles and has black and white shoes. Alvin was also given a red baseball cap and is the shortest of his brothers.
In Chipmunk Punk, Alvin wears clothes similar to The Alvin Show with the red sweater and matching hat. He also wears white and dark grey shoes and has a box cut instead of his regular hair as to match the visual style of the cover.
When the Alvin and the Chipmunks series was created, Alvin wears a red sweater with his signature yellow 'A' and a baseball cap. He also wore white and blue pattern sneakers. In the early episodes, Alvin's eye color was black but, as the series progressed, his eye color changed to blue. In some episodes, Alvin wears light red footie pajamas with an 'A' on it, while in others, he wears a red t-shirt with a yellow 'A' on it along with red pajama pants.
In the CGI/live-action films, Alvin only wears a red hoodie with a yellow 'A' on it. His appearance was modified to look closer to a real life chipmunk. He has brown fur as well as brown eyes. In the 2007 Alvin and the Chipmunks, Alvin is only seen wearing his signature cap twice; the first time on a magazine cover and the second at the end of the movie.
In ALVINNN!!! and The Chipmunks, Alvin wears a red and blue-hooded sweater with his signature yellow "A" on it, which has a hole in the left sleeve, blue jeans, and red/orange/white converse sneakers. Alvin regains his signature red cap as a common accessory, but it now has green beneath the visor and red-orange on the top-visor. He has auburn hair and blue eyes. His pajamas consist of a t-shirt with a winged guitar illustration.
The relationship between Alvin and Dave is frustrating for the two of them at times. Frequently, Alvin will disobey which makes Dave scream his signature catchphrase "ALLLVIIINNNN!!!!", to which Alvin replies with a loud "OKAY!!" Although they can both irritate each other, they really love and care for each other.
In The Alvin Show, Alvin and Simon didn't usually argue or have a developing relationship until the 1980's series. Generally, Alvin and Simon have a love/hate relationship. They get frustrated with one another, mainly because of their differences. However they eventually work things out. In Alvin and the Chipmunks Meet the Wolfman Alvin and Simon show a brotherly bond while working together to find a cure for Theodore. It is obvious Alvin cares for Simon, because in Bully For You for instance, he wanted to help save Simon from Derek, the school bully. Despite Simon’s disagreements about Alvin’s plans, Alvin does manage to talk him into it.
Alvin's relationship with Theodore can sometimes be hard for Theodore. Sometimes Alvin enjoys teasing Theodore; it usually upsets Theodore, which Alvin doesn’t realize. Although Alvin is sometimes rude to Theodore, he cares and stands up for him as shown in Alvin and the Chipmunks Meet the Wolfman where he saved Theodore from Nathan, the school bully. Alvin also drags Theodore into his schemes.
Alvin and Brittany have a competitive relationship, especially due to both possessing very big egos. They are constantly at odds with one another and argue, but they do show that deep down they love each other. They are shown in the future as married with twin boys.
Alvin and Jeanette are friends. In My Sister The Weirdo, is one example in which Jeanette trusts in Alvin's abilities, such as his confidence, to help herself out. Jeanette can sometimes get angry with Alvin, but she's seem more caring for Alvin.
Alvin: That's it! I can't take this anymore. I can't! I give up! I'm sick of struggling for survival, competing with gophers and earthworms and that loser sparrow who always takes my nuts! And I'm especially sick of this stupid! Stupid! TREE!! - (Alvin and the Chipmunks)
Alvin: Dave likes to wear, dirty underwear, with little hairs! - (Alvin and the Chipmunks)
Alvin: Our parents were hippies. They left early to join a commune. - (Alvin and the Chipmunks)
Alvin: We're not performing monkeys, Dave! Why do we have to sing for that guy anyway? - (Alvin and the Chipmunks)
Alvin: That hurts, Dave. That really hurts. - (Alvin and the Chipmunks)
Alvin: You should have kissed her, Dave! She wanted you! - (Alvin and the Chipmunks)
Alvin: MAJOR ROCK STARS. - (Alvin and the Chipmunks)
Alvin: You'll never take us alive!!! - (Alvin and the Chipmunks)
Alvin:You talking to me? You talking to me? I'm the only one here, so, you must be talking to me! - (The Squeakquel)
Alvin: Oh, relax. It's like Ryan says, who's going to beat singing chipmunks? - (The Squeakquel)
Alvin: I never thought I'd say this, but...pink is my new favorite color. - (The Squeakquel)
Alvin: Got it. Straight to the top. Ironic. - (The Squeakquel)
Alvin: I will create a spark by striking this rock with my Swiss army knife...which Dave took from me. - (Chipwrecked)
Alvin: Okay, this is crazy. Building a shelter was your idea! Yours!!! - (Chipwrecked)
Alvin: Hey, guys! Look what I won! Isn't he cute? Look at that face! - (The Road Chip)
Alvin: I didn't listen to Theodore's song because I thought the only rapper he cared about was a candy wrapper. - (Lil' T)
Alvin: Ah, I see your problem. It's obvious. This has been written by aliens. - (Un-Send!)
Alvin: I can't let you get hurt, Jeanette. My reputation isn't worth it. - (Wacky Wednesday)
Even though Alvin is the oldest by five minutes (as stated in the 80s episode Grounded Chipmunk), many fans believe that he is younger than Simon in this series since Simon is taller and more mentally mature.
Alvin's age is unknown in the CGI/live-action films, though the 2007 movie novel states that Simon is the oldest.
In the CGI/live-action films, Alvin has only worn his baseball cap in the 2007 movie (in a magazine and at the end).
In the CGI/live-action films, Alvin is also depicted as having the ability to speak basic French unlike in both the 1980's animated series and The Alvin Show in which he is shown to be unable to speak French in "Petit Papa Noel" from A Very Merry Chipmunk, and he is shown to wish he could speak French in The Alvin Show musical segment "I Wish I Could Speak French."
According to Romancing Miss Stone, Alvin says that his birthday is nearby and he is turning nine years old (along with his brothers). However, later on in the series, they are stated to be eight years old several times, despite being 4th graders.
Alvin's attire has changed many times throughout the franchise with him wearing the most clothes in the new CGI series and him wearing the least amount of clothes in the live action/CGI films.
During the 2000-era, Alvin was, and is, known as the self-appointed "leader" of the group. And, presumably meaning The Alvin Show, he suffered from small "munk" complex and tried to make up for it with his grand schemes and animal magnetism.
He is described as an "emotional roller coaster," leading some fans to believe he may have bipolar disorder or a similar condition.
In the CGI/live-action films, Alvin is shown to have great hands when catching: in The Squeakquel (when he joins the football team and makes a game-winning touchdown catch), Chipwrecked (he catches a pocket knife with one hand in mid-air), and The Road Chip (he catches a ring with one hand in mid-air, with a fully-extended body).