The title character. Once a street-wise youth in Philadelphia, a skirmish with a bully causes Will to be sent to live with his wealthy relatives in Bel-Air, California. The show focuses on Will living and interacting with the upper-class society and residential celebrities. Later on, there's more focus on Will's college life.
Character Development: Primarily regarding his relationship with Carlton. Early on, Will gives Carlton grief about not being black enough, but eases off once he sees Carlton face discrimination from other blacks for exactly this and realizes how asinine and unfair it is.
Will was pretty much sought to retain his free-will "Homeboy" lifestyle when first settling in Bel-Air, but has become more accustomed to it and more open about his knowledge of numerous references.
The Danza: Played straight with an undertone of subversion: Real-life Will's full first name is "Willard." In-show, Will's full first name is "William." It also applies to his last name of Smith, too.
Disappeared Dad: Will's father Lou took off on the family when he was a baby and left his mother to raise him. When Lou comes back, he briefly tries to reconcile with Will but proves he's still the same selfish bastard he always was when he effectively abandons Will once again. This led to one of the series' biggest Tear Jerkers when he tearfully asked Uncle Phil:
I Have No Son: Inverted with Will and his father Lou. When Lou comes back into Will's life after having run out on him 14 years ago, Lou then abandons him again for another trucking job. This is the final exchange Will and Lou share:
A successful attorney (later appointed a court judge) who doesn't try hide his reluctance to Will settling in with the Banks. Spends a good portion of the show dealing with Will's antics and help fix any mess made.
Big Eater: It ends up giving him a heart attack in an episode.
Bald Black Leader Guy: Not a leader, per se, but more than a few plots show that he's in charge of the family.
Bumbling Dad: Very much averted. He has his moments of stupidity, but he's portrayed as competent and knowledgeable way more often than other sitcom dads.
Parental Substitute: Eventually proved to be more of a father to Will than his real father ever was.
The last episode effectively spells this out and makes it clear that the two consider their relationship that of father and son rather than uncle and nephew.
Not So Stoic: She's usually more reserved and reasonable than Phillip, but she can lose it when a matter specifically bothers her.
If she starts taking her earrings off, be warned.
The Other Darrin: She was originally played by Janet Hubert-Whitten. From the fourth season on, she was replaced by Daphne Maxwell Reid (there was even a lampshade about the fact that Vivian's skin color change, as the original actress had dark brown skin while her replacement was a light-skinned black woman).
The middle child of the Banks family who strives to get into Princeton and be a successful lawyer like his dad. More confident in the law and order in general, Carlton's at odds with Will more than frequently, though by the later half of the series he becomes The Lancer.
Angst Coma: When Carlton fails to get into Princeton.
Adult Child: When he and Nicky go to see Dougie, they're equally excited.
Characterization Marches On: Carlton was introduced in Season 1 as an incredibly preppy and pompous Smug Snake playing no more than a rival or Foil to Will. Recurring emotional breakdowns and being a Butt Monkey occurred in the next seasons; and eventually became the complete nerdy goof everyone loves and remembers.
The spoiled elder child of the Banks family, Hilary's socialite bent on looked highly upon her peers in the upper class. She's also leeches off her parents' fortune and ignorant of how life outside hers really works.
Character Development: Originally shallow and lacking of self-confidence for being a jobless college dropout, she is shown to be more and more jovial for each successful job she takes on from Season 2 onwards; she ends up starring in her own hot talk show and moves to New York.
The youngest child of the Banks (until Baby Nicky arrived), she very much looked up to Will. Gradually, she became bent on being less of daddy's little girl and more open and a bit rebellious, even out of Will's control. She is the only one of the Banks children to have, more or less, normal adolescence; having common teenager issues.
Bratty Teenage Daughter: Averted, except in one case where she had a singing career and got a big head, but when her album didn't sell, she went back to being her sweet self.
The youngest of the Banks children, born during the run of the show. But don't let that make you think he didn't have any Character Development, he grew as much as the others did.
Children Are Innocent: And Santa tells Will to keep Nicky that way for as long as possible.
Overly-Long Name: He starts out as Nicholas Andrew Banks, and the first names of the members of Boyz II Men were added on the day of his christening.
Soap Opera Rapid Aging Syndrome: Lampshaded immediately, with Jazz replying that he's going back to Philly where everything makes more sense than it does in California.
Chekhov's Shirt: Since they constantly reused the same clip of Jazz getting thrown out of the house, they maintained continuity by having Jazz wear the same shirt in almost every episode he gets thrown out. It gets to the point where you can tell the Running Gag is about to occur if you see him wearing the shirt.
Limited Wardrobe: Because of his being thrown out of the house is Stock Footage, he always wears the same outfit when he's about to get thrown out.
Running Gag: His tendency to get thrown out of the Bankses' house.
Inverted, subverted, and averted a couple of times, such as when he was thrown into the house, when Jazz threw Uncle Phil out the house, and when Jazz did something so horrible that Will doesn't think he's worth kicking out of the house.
Viola "Vi" Smith (Vernee Watson-Johnson)
The Other Darrin: A small case, but who did play Will's mom in the opening sequence?
It's the "mom figure" used in Smith's DJ Jazzy Jeff and Fresh Prince videos (particularly "Parents Just Don't Understand").
Jerkass: Judge Robertson was apparently idealistic in his younger days, but as of the show's timeline he's become extremely selfish, misogynistic, deceitful, and a classic example of a corrupt politician. He was such an awful human being that at his funeral, everyone was there to celebrate his death, and they even applaud Will when they learn that he caused it.
You Look Familiar: Hemsley also made two separate appearances as George Jefferson, alongside Isabel Sanford as Wheezy.
Unrequited Love Switcheroo: It's implied that Jackie had a lingering crush on Will before he left and that he hadn't quite realized his feelings until he was gone, thus explaining why he never called because he missed her too much and didn't want to come to terms with his feelings. When she comes out to Bel-Air, Will starts to fall for her again, though the situation suffers from Aborted Arc and is never resolved.
Lisa Wilkes (Nia Long)
You Look Familiar: Long previously played another girlfriend of Will's three seasons earlier.
