Thurston Howell III is one of the main characters of the show. He is the head of Howell Industries and an excellent businessman, which has made him a multi-billionare.
The Howell's were so rich that they took thousands of dollars with them on the supposed three hour tour. On the mainland they had a butler, an upstairs maid, a downstairs maid, a cook, a gardener, a chauffeur, and other servants, even a butler for their butler. Because of this, Mr. Howell wasn't accustomed to physical labor, which often forced the other castaways to work while Mr. Howell sat in a lawn chair and watched. The Professor once said about him: "Mr. Howell always manages to disappear when there's work to be done." It was only rarely that Mr. Howell worked, although here the term "work" can be used loosely. Such rare occasions include when he helped tar a hut, which, of course, Gilligan ruined (Home Sweet Hut). Even on the island, Mr. Howell was so desperate for a servant, partially for his wife, that he bet Gilligan's services for the skipper in a turtle race so that he could become their houseboy (They're Off and Running). Mr. Howell is actually a billionaire and one of the world's richest men, inherited from his father. He met his wife "Lovey" at Harvard and married her in 1944. He remembers it as the day Consolidated General jumped 17 points. Although they've been married 20 years, they both admit that the last 5 years haven't been much of a picnic. But still, Thurston can be remarkably sentimental and romantic with Lovey. Known as "the Wizard of Wall Street", he has been convicted 6 times on antitrust suits, and investigated every year for income tax evasion. He owns up to 12 corporations, and as chairman of the board, has 5,000 employees and an office on the second floor. He also has interest in aviation, oil wells, the Thurston Howell Battery company and owns a movie studio. He is also apparently a member of at least two yacht clubs. He prides himself as being a Harvard graduate and a registered Republican. He has homes in Palm Beach, Paris, Newport, New York, Monaco, and all 50 states. Thurston has 20 suitcases just for himself. Howell displays little tact, blames the Skipper for the shipwreck, and is always trying to break the castaways' laws and bribe others. He is sneaky, untrustworthy, conniving, greedy and corrupt. Yet, when it comes to the lives of his fellow castaways, he's always exceptionally generous and caring. He refuses to do manual labor, preferring instead to hire Gilligan to work for him. He usually spends his day relaxing with his wife, Lovey, on the bamboo lounge chairs, sipping tropical drinks, and listening to the stock market report on the radio (which is his). He also enjoys playing golf with bamboo and seashell clubs, and reading his only copy of the Wall Street Journal every day. He finds it comforting that the market never goes up or down.
The Howells' have more clothes than the rest of the castaways combined. They always have an outfit to match the occasion, no matter what is going on. They probably take clothes with them wherever they go.
In addition to a lot of clothes, Mr. Howell brought along numerous objects and belongings in around twenty to twenty-five suitcases, including a briefcase (filled with stocks, certicates, bonds, IRS forms and checkbooks), a small case with the keys to all his properties, an alligator skin case with his medicine and tranquilizers, cases and trunks of cash (around $500,000), his teddy bear, bottles of liquor and brandy, a copy of the Wall Street Journal, a solid gold camera and flash, binoculars, a large net, a butane lighter, a money-changer, two fencing outfits with masks and sabers, wigs for George and Martha Washington, an Admiral's cap and a clock that he sold to the Skipper for the Professor to make a bomb for the volcano.
- In Meet the Meteor, if Mr. Howell had aged 50 years, he would have been 100 years old-thus his age is approximately 50. (Jim Backus's real age was 53.)
- He mentions being raised by a nanny and not being allowed to make mud pies as a child. The butler made them for him and took his spankings as well.
- He is infamous for sleeping with a teddy bear called "Teddy."
- Mr. Howell is a graduate from Harvard University, often referring to people he considers as primitive as "a Yale man". He is also a member of the "Harvard Club." and a member of SMU (Super Millionaires University) and the Union League Club.
- Mr. and Mrs. Howell were married by the Reverend Buckley Norris. His father-in-law gave him a deed to a Oklahoma Oil company named Dust Bowl which he thought was a stadium.
- Back home, he is a member of the Sunnybrook Yacht Club.
- He is a Republican.
- Both Mr. and Mrs. Howell are bird watchers.
- He occasionally wears eyeglasses.
- He enjoys occasional bottles wine and brandy, but in Nyet, Nyet, Not Yet, he reveals he can't handle vodka.
- Although the theme song states that he is a millionaire, the radio announcer in Two on a Raft refers to him as a billionaire. in Will the Real Mr. Howell Please Stand Up?, it is revealed that during the Great Depression, he lost money and became just a millionaire. His neighborhood is so exclusive that the "slum area" is just for mere millionaires!
- The Howell's hometown is never identified, although it is known they have several homes. Their main residence may be in Newport Beach, New York (mentioned in Gilligan Meets Jungle Boy) or in Southampton, New York.
- In Love Me, Love My Skipper, it's mentioned that the Howell's had a ranch that developed into a small nation.
- When Mr. Howell learned an imposter is claiming to be him and is spending his money, he is so enraged he tries to swim the Pacific twice to get his money back!
- In Gilligan's Mother-in-Law, the part of the Chief's wife is played by Jim Backus's real-life wife, Henny Backus.
- One of the few times both Howells have to work is when egocentric Hollywood director Harold Hecuba has both Howells become his servants as a butler and maid in order to get off the island! (Likewise, in Agonized Labor, when Mr. Howell thinks he's broke, he tries being a butler and fails!) He is also a terrible cook.
- In one episode, Mr. Howell's turtle beat the Skipper's turtle in 40 races! After the last race the Howell's won Gilligan as a servant, but Gilligan turned out to be so bumbling and inept that the Howell's deliberately tried to "lose" to the Skipper. First, Mrs. Howell changed the markings on the turtles; then Mr. Howell changed the markings again then the Skipper changed the markings and then Mr. Howell changed the markings, which after his turtle won resulted in Howell crying in agony over having Gilligan as a servant! Finally Mr. Howell made a bet with the skipper who lost-and won back Gilligan! In one of the early episodes Mr. Howell .25 Cent bet with Gilligan over putting grows to 3 million dollars! Howell "sells" Gilligan ownership stock in an oil company which suddenly "strikes" oil in Dustbowl, Oklahoma. Mr. Howell is also a pool shark, conning the Skipper into owing twelve million dollars over pool games and then takes the stock certificate as payment. Later, the oil strike is revealed to just drilling into a oil tanker that was covered by sand! In the The Hunter, Mr. Howell wins a bet from the Skipper on the Dodgers baseball game. Mr. Howell claims the Skipper owns him 300,000 mangos while the Skipper retorts Howell should deduct it from the 960 bananas Mr. Howell owes the Skipper from gin rummy!
- In the Nyet, Nyet, Not Yet episode, Howell is actually pleased when the Russians refer to him as a capitalist exploiter!
- In the Lord Beasley episode, Mr. Howell passes out after drinking too much fermented berry tea. In the Nyet, Nyet, Not Yet episode, he claims the only alcohol he can drink is small amounts of wine, although in the Splashdown episode, he has cognac. He keeps champagne, claimed to have "sold" New York Grand Central Station over drinking Dry Martinis! He is also President of a wine-tasting club. He also has a drink and straw in his hand in most scenes.
- In the Allergy Time episode, the nearest hut to the Howells hut on the left is that of the girls hut of Ginger and Mary Ann. In this episode, it is revealed that Mrs. Howell talks in her sleep and Mr. Howell sleepwalks.
- Mr. Howell takes a stroll at 9:00 and keeps his swagger stick pointed toward Oxford England; he also has high blood pressure and has to be on a diet; in It's a Bird, It's a Plane, Howell claims to become dizzy when standing on his tiptoes!
- When the Mosquitoes come to the Island on Don't Bug the Mosquitoes, which Mr. Howell cant stand-he wears earplugs throughout their concert!* A running gag is that Mr. Howell leaves a different will after a life-threatening crisis. In X Marks the Spot, Mr. Howell writes a will leaving his money in the First National Bank to needy children. (Those who weren't born in Beverly Hills!). His money in the Second National Bank to fight unnamed diseases and his money in the Third National Bank to the First National Bank! In Meet the Meteor, when Mr. Howell is dictating his will, he leaves to his nephew Perry his polo pony "Sea Biscuit" and his four Golf Country Clubs, including Pebble Beach! He also forgives his nephew's wife's debt to him of $1.42! In another episode, he dictates his will again leaving the fellow castaways the beneficiaries.
- In the dream sequence, The Sweepstakes, Mr. Howell is a prospector, who after 40 years finds gold and then is going to be lynched because he can't produce a receipt for his claim to meet his monetary promises for the rest of the castaways. (In fact, he is seen putting the receipt in his pocket!)
- Jim Backus appears in the three sequel moves of Gilligan's Island. In the last movie, The Harlem Globetrotters on Gilligan's Island, Jim Backus made a brief cameo as Thurston Howell III.