- “My friends, we are about to embark on the most odious, the most evil, the most diabolical scheme of my illustrious career. A crime to top all crimes. A crime that will live in infamy! Tomorrow evening, our beloved monarch celebrates her Diamond Jubilee and, with the enthusiastic help of our good friend, Mr. Flaversham, it promises to be a night she will never forget! Her last night, and my first, as supreme ruler of all Mousedom!”
- ―Ratigan explains his scheme to his henchmen[src]
He is the story's version of Professor James Moriarty from Sir Arthur Conan Doyle's Sherlock Holmes stories, and serves as the adversary to the Sherlock Holmes counterpart Basil of Baker Street. He has cited the "Big Ben Caper" and the "Tower Bridge Job" as two of his most notorious criminal operations.
- “Oh, I love it when I'm nasty.”
Ratigan has a variety of henchmen that follow him, including his overweight pet cat Felicia, Bill the Lizard, a small mouse named Bartholomew, and his right-hand man, a peg-legged bat named Fidget. The rest are a large gang of mice including Red, Snakes, and Peewee Pete. Personality-wise, Ratigan is very charismatic, calm, and calculating, but can easily be sent into a violent rage at the mention of Basil or by the incompetence of his minions. He has a very dark, malicious sense of humor and an inflated ego. Unlike most Disney villains, Ratigan is an ebullient, lip-smacking jester who has a tendency towards big movements and long rants or speeches.
Even though he is one, Ratigan detests, above all else, being referred to as a rat, preferring the description of a "big mouse," and fed Bartholomew to Felicia when Bartholomew calls him the "world's greatest rat" while intoxicated. He can easily be identified as a rat since he has five-fingered hands, while all the other mice have four fingers. Also, the mice in the movie have fur-covered tails that much thinner than Ratigan, who has a pink, fleshy segmented tail. Despite his hatred of being labeled as such, he possessed enough self-control to barely react when Basil referred to him as a rat, which is evidenced with two instances in the film: The first, right after he trapped Basil and Basil called him a sewer rat, Ratigan retained his cool demeanor, only closing his watch, and the second time, when Basil revealed his survival after the literal breaking down of the fake Queen of Moustoria by finishing her sentence of Ratigan being a rat, only growling in irritation. In the Basil of Baker Street book series, Ratigan's first name is revealed to be Padriac, and he is in fact, portrayed as a mouse (in contrast to his depiction in the movie).
Ratigan is a towering rat with grey fur dressed in a dark grey suit complete with a long black cape with a red underside. His face is shaven and has yellow eyes with lavender circles around them, above them are thick eyebrows. Although he lavishes himself as a mouse, he has rat-like characteristics, such as sharp fangs and fingers, a large nose, and a long, pink tail. On his head, he wears a black top hat with a grey band, which covers his black combed hair. His suit includes a high white collar and a gray vest with buttons on it with a pink-and-purple striped cravat. On his hands are white gloves and cuffs with golden cufflinks. He is always seen carrying a gold cane.
However, when Ratigan becomes completely enraged, he becomes incredibly feral, running on all fours in a hunched position. His hair becomes messy and his clothes become torn exposing his intimidating physique as Ratigan becomes vicious as he obtains a more rat-like appearance. His nails and teeth also grow longer and gnarly.
Ratigan makes plans to take over London by replacing the Queen with a robotic fake built by a toymaker named Hiram Flaversham, whom he has Fidget kidnap. He will then have the real Queen fed to Felicia, ensuring his reign as permanent supreme ruler of all Mousedom. Although Flaversham is reluctant to help, Ratigan threatens to harm the former's daughter Olivia, and this gets the prisoner back on course. He then reveals his plan to his followers, but not before having one gobbled up by Felicia for "insulting" him. Just as his plan is nearing completion, Basil and his new companion, Dr. David Q. Dawson, bring Olivia along and they are able to intervene in the final stages. Learning of their involvement from Fidget, Ratigan constructs a very complicated trap consisting a barrage of life-size weapons to pummel Basil and Dawson before leaving for Buckingham Palace with his thugs and the Robot Queen boxed in a package, flying off in his blimp. However, unbeknownst to Ratigan, Basil uses the trap to free himself, Dawson, and Olivia.
At Buckingham Palace, Ratigan's plan is set into motion. His thugs, disguised as guards, enter the Queen's room, where they unbox the package to reveal the Robot Queen, to the confusion of the real Queen. As the robot chases her, Ratigan reveals himself. The real Queen orders the "guards" to seize him, but Ratigan, shouting into a speaker built into the robot's controls that makes the Robot Queen speak, orders his thugs to seize the real Queen, then rings his bell to summon Felicia. As the Diamond Jubilee takes place, the Robot Queen names Ratigan as her new "Royal Consort", and Ratigan, dressed in an ornate robe, immediately presents himself in front of the gathered citizens of Mousedom, terrifying them. Ratigan then proceeds to read over his long list of tyrannical laws, one of which is a heavy tax policy for people he deems "parasites", such as the elderly, infirm, and even children; meanwhile, Basil, Dawson, and Olivia rush to the palace, arriving just in time to save the real Queen. They then take control of the Robot Queen and reveal the scheme in front of the citizens, foiling Ratigan's plans. The citizens then ambush Ratigan and his thugs, but Ratigan fights off his attackers by shedding off his robe. Just then, Fidget reveals that he had captured Olivia again, and Ratigan, rushing over to Fidget, orders Basil, Dawson, and Flaversham to remain where they are, threatening to kill Olivia if they attempt to stop his escape. The three mice quickly rush outside the palace and improvise a flying apparatus to pursue Ratigan above the city. Fidget, who is pedaling Ratigan's blimp to speed it up, cannot take the extra weight and tells Ratigan they have to lighten the load, meaning to throw Olivia off the balloon. Ratigan, out of sheer bad temper, instead throws Fidget (who cannot fly) off the blimp and into the Thames. With Fidget gone, Ratigan pedals the blimp himself. Basil jumps onto the blimp, distracting Ratigan and causing the blimp to crash into one of the clock faces of Big Ben.
Inside the clock tower, Ratigan recovers, seizes Olivia in one hand, and prepares to ambush Basil. Basil, however, notices him, and the two fight atop the gears of the clock tower. With Olivia's help, Basil traps Ratigan by throwing his cape into the gears. The two mice then escape and Basil is able to take Olivia to safety. This finally sends Ratigan over the edge. Breaking free from the gears, he pursues Basil, tearing his clothes in the process and transforming from a very formal, composed rat to a highly savage one. Ratigan tackles Basil and they both fall onto the clock's hour hand; Ratigan stops Basil from reaching the others. Finally, he extends his long, strong fingernails and begins scratching, punching, and strangling Basil continuously. The attack leaves Basil with torn clothes and several wounds. Attempting to finish him off, Ratigan knocks him off the clock hand and yells in triumph, thinking he has won. However, Basil called him, saying to him that the game was not yet over. Ratigan glances down and sees Basil holding on to the broken blimp. Basil rings Ratigan's bell which he used to summon Felicia, realizing that he stole the bell during the fight and already lost the battle. Suddenly the clock bell tolls, causing Ratigan to lose his balance, and plunge off the hand, taking Basil with him. Basil manages to save himself while Ratigan plummets to his death.
His death later makes headlines in newspapers (via a sub-headline that reads "Time Runs Out for Ratigan"), of which one copy is kept by Basil.
Ratigan's most notable cameo on House of Mouse was in the episode "Donald's Lamp Trade", in which he tries to lure Dr. Dawson with cheese on a mousetrap, but Basil stops Dawson and tells him it's a trap, at which point the nearby Ratigan groans, "Curses!" He is also seen with several other mice in "House of Scrooge".
Ratigan can also be spotted seated alongside other Disney villains and Fidget in recurring crowd shots. This shot is also included in Mickey's House of Villains.
In an episode of Quack Pack, Ratigan can be seen on the box art of criminal trading cards.
Professor Ratigan is one of the villains brought back to life to be imprisoned in the Isle of the Lost. It is mentioned once that he and his crew went to Ursula's Fish and Chips Store and every time they go there, Ursula chases him out.
Ratigan was once a walkaround character at the Disney parks during the film's initial release. But he has been retired, rumour has it that it was because he frightened children. His last appearance was at a special event at the Magic Kingdom in 2004.
- Ratigan is shown to have an animation flaw. If you look closely during the course of the film, Ratigan has five fingers on his hands. However, during the battle sequence from when he goes feral to when he falls to death, he is shown to have four fingers on each hand minus when he flared his claws and before he punches Basil off the clock hand.
- Ratigan seems to grow in size during his breakdown in Big Ben, and his claws are shown extending out of his hand. This transformation could be compared to that of a stereotypical Werewolf.
- According to a deleted lyric in "The World's Greatest Criminal Mind", the Tower Bridge Job involved hurling several innocent mice into the River Thames and then shooting whoever attempts to come up to the surface.
- Vincent Price, the voice of Ratigan, said that doing Ratigan was his favorite role because he had two songs written for him.
- Ratigan is the first Disney villain to just fall to his death since the disguised Queen from Snow White and the Seven Dwarfs, Disney's first feature length film. Maleficent's death included falling, but she already suffered a fatal wound from the Sword of Truth piercing her heart before falling to her death.
- In the novel that the film was based on, Ratigan is actually a mouse, despite his name. This was changed for the film.
- Ratigan is the first Disney Villain to sing his own villain song since Kaa in 1967.
- Even though it is believed Ratigan died in the climax, the same newspaper that says Basil and Dawson were thanked by the Queen also says "Time runs out for Ratigan". This implies he, like Basil, survived but is presumably dying of his injuries from his fall but it can also imply Ratigan is on the brink of facing prison for his crimes. And some Italian comics with Basil say that everybody thought that he was dead when he fell, but that he in fact survives; and so he appears in a few stories.
- There is a level in Disney Heroes: Battle Mode called Ratigan Street, named after Ratigan.