Lyle Tiberius Rourke was born in 1860 and learned the ways of military life at an early age. In 1864, his father, a cavalry officer named Lt. Col. Jackson, was killed in battle during the Civil War. After repeated expulsions from boarding school for fighting, Rourke resolved to follow in his father's footsteps and joined the military at age fifteen. There, he exhibited a remarkable talent for leadership, owing to his analytical mind, charisma, and refusal to acknowledge the white flag surrender. He married in June 1887, but his wife left him after only four months.
He held numerous expeditions during his career, most notably leading the Whitmore Expedition to Atlantis.
As has been the case in their previous films, directors Gary Trousdale and Kirk Wise wanted the film's villain not to be the usual mustache-twirling bad guy. They wanted the character to have complexity by not making him inherently evil, but rather greedy. The idea being that they wanted a three-dimensional character as opposed to a two-dimensional villain.
The supervising animator of Rourke was Michael Surrey. At first, Mike was excited at animating the character because villains are generally the most desired characters for animators as they are generally allowed to do whatever they pleased. Mike then realized that it was not going to be like that early on as Rourke was not the typical type of villain. It was not until the climactic battle in the volcano that Mike was able to really animate the villainous scenes he had been hoping to do.
James Garner provided the voice of Rourke. While Tommy Lee Jones, Jack Davenport, and Kurt Russell were among those also considered for the role, Garner was chosen for his extensive acting background in action films, westerns, and war movies, making his voicing a character like Rourke fit him like a glove. Garner was noted for having fun doing the role and was impressed with Trousdale and Wise's ability to direct what he describes as an ensemble piece.
Rourke is seemingly composed, pragmatic, and a reasonable figure of authority. In truth, he was extremely manipulative, scheming, cruel, and violent, having no qualms against harming or threatening others to get what he wanted, as he planned to steal the Heart of Atlantis to sell for a high price and didn't even care if the Atlanteans would die as a result.
According to Rourke, he also has quite a bit of control over his temper, as he tells Milo and congratulates Milo for setting it off.
Due to being expelled from boarding school numerous times at the age of 15, he possesses a strong sense of anti-intellectualism as he believed that intellectualism prevented people from 'playing dirty' in order to become successful in life.
Initially, Rourke wore standard military uniform that usually army commanders wear. After the pyrefly attack, he loses his military coat. This transition symbolizes who Rourke truly is as a person. After being crystallized by Milo during the climax, his clothes was fused to his body as he became a crystalized humanoid monster, a true reflection on his insanity. Cracks appear on his body with beams of red light shining through as every movement causes him extreme pain before being obliterated to pieces.
Rourke leads the expedition to find the Shepherd's Journal in Iceland with Milo's grandfather Thaddeus Thatch. When Thatch is not looking, Rourke rips out a page concerning a giant crystal which he later uses to convince virtually everyone else on the forthcoming expedition to Atlantis to retrieve it and sell it on the black market for a hefty sum.
As commanding officer of the expedition, he is primarily responsible for making the decisions that will ensure the mission's success as well as the survival of his crew. This includes the belief of there being acceptable losses in his attempt to defend the Ulysses from an attacking Leviathan before ordering all hands to abandon ship.
He has little contact with others outside of his directing orders, preferring to stand apart. When the expedition is dropped into a cavern while escaping the attack of fireflies, he recognizes a possible exit route through the top of the volcano they are in. With the discovery of Atlantis being alive and thriving, Rourke maintains to a hesitant Helga Sinclair that their primary objective remains as planned.
After attempting to learn from the Atlanteans where the crystal might be, he turns to Milo Thatch to decipher the stolen page, but not before Milo discovers Rourke's treachery when the young cryptographer sees his former allies armed with guns. As a result, Milo refuses to play along with him, and Rourke, in turn, becomes more forceful and has a gun pointed at Princess Kida He then has the doors to the king's chambers blown open and demands King Kashekim Nedakh explain the riddle that reveals the location of the crystal, going so far as to strike the already dying king in front of a horrified crew. Sitting on the throne and threatening to execute the king, Rourke manages to figure out the riddle on his own and proceeds to descend into the chamber with Helga dragging Milo and Kida along.
In the Crystal Chamber, while Milo and Rourke argue over how the crystal is to be retrieved, Kida is called upon by the Heart of Atlantis and is bonded with it. Rourke then has Kida sealed up in a container and prepares to leave. Milo pleads that their actions will kill the Atlanteans, but Rourke does not care and decks him. Rourke punches Milo in the face and then breaks his picture with his foot. Outraged, Audrey, Vinny, Cookie, Packard and Mole abandon Rourke to join Milo's side, leaving Rourke with only Helga. Unmoved, Rourke leaves his former crew in the dying city. Rourke then has the bridge detonated to prevent them from following in an attempt to stop him.
Rourke has the top of the volcano blown open and has a hot air balloon ascending with the container when Milo and the others arrive in flying stone fish vehicles. During the chaos, Milo crashes his stone fish into one of the balloons, causing it to descend. With all of the extra weight having already been thrown off, Rourke tosses Helga off in an act of self-preservation. However, a dying Helga gets back by shooting the hot air balloon with a flare gun, causing it to set on fire and descend at a faster rate.
Losing what's left of his sanity, an enraged Rourke begins to take his aggression out on Milo and grabs a fire axe to kill him. He hits a glass cover of the container, with glass shards becoming embedded with the Heart of Atlantis. As Rourke holds Milo up for a killing blow, Milo cuts him with one of the shards and he begins to transform into crystal form. Rourke still attacks, but a chance situation causes him to be hoisted into the still moving propellers, destroying him for good.
When Milo's friends eventually return to the surface, they reenact a false story with Preston regarding the fates of the other crew members after explaining the truth of the situation to him earlier. When Preston "asked" about Rourke, Dr. Sweet responded that the crooked commander suffered a nervous breakdown and that he "shattered to pieces", while Cookie added that he was "transmogrified" when Packard threatens to whack him with her umbrella, and Cookie immediately restates his answer to simply "missing".
Rourke appears briefly in "Donald Wants to Fly", watching Kida fly above his head in quiet awe.
- Rourke's fight with Milo was similar to the fight between Gaston and the Beast, even having Rourke trying to smash an ax against him. Coincidentally, both Beauty and the Beast and Atlantis: The Lost Empire were directed by the same two men (Kirk Wise and Gary Trousdale) and were released within roughly a decade of each other.
- Rourke's treachery and eventual betrayal was actually foreshadowed several times early in the film.
- When Whitmore shows Milo the photographs of all of the explorers he will be traveling to Atlantis with, Rourke's photo is the only photo that's partially obscured with only half of his face visible. Also, along with their photos are small sheets of paper showing each of the explorers' profiles and biographies. Since we don't see the other half of Rourke's face, we don't see his biography at all, implying that he's deceitful in nature.
- Yet another clue to Rourke's betrayal includes some of his early lines in the film, especially those containing either the words "rich" and/or "money", with the most obvious example of this being his line, "This will be an enriching for all of us."
- Also, shortly before Ulysses was submerging, Whitmore is seen crossing his fingers behind his back, implying that he did not take full trust on the expedition led by Rourke.
- Also, when the remaining crew members are forced to evacuate the submarine, Rourke is the first to enter the escape pods. In real life, the captain is always the last crew member to evacuate a sinking ship (hence the phrase "go down with the ship"), so this is often considered disrespectful to maritime culture.
- When the crew is allowed to enter the city, Rourke orders his soldiers to stay behind at the volcano base, and "salvage what [they] can", which hints that he's covering up a secret agenda of his own.
- When Helga informs Rourke that there was not supposed to be people in Atlantis and that it changes everything, a determined Rourke replies "this changes nothing", implying that he does not care of whatever fate he brings to the Atlanteans. This sentence, however, is disrespectful against professional ethics and morality in real life as it emphasizes pure ignorance on the needs of others.
- After Rourke abandons all of his teammates except for Helga along with Milo and the other Atlanteans in Atlantis, as he and Helga are leaving Atlantis with the crystallized Kida, he tells himself, "P.T. Barnum was right." P.T. Barnum was a famous American showman who coined the phrase, "there's a sucker born every minute." But historically, he never did as Barnum was not the kind to disparage his customers.
- Rourke's middle name, Tiberius, could be a possible reference to Captain James Tiberius Kirk from the show Star Trek, of which Kashekim Nedakh's voice actor Leonard Nimoy played Spock.
- Rourke has at least 90 henchmen (including himself and Helga), given the fact that the Ulysses was supposed to have 200 crew members at the start of the expedition, and that half (100) of said crew were all killed in the Leviathan attack, and that only seven crew members (Milo, Vinny, Molière, Audrey, Dr. Sweet, Mrs. Packard, and Cookie) actually survive at the end.
- For a while, Rourke (and to a much lesser extent, Helga), was the most marketed character from the film following Atlantis' release and was therefore officially the most popular character from that film. However, Rourke's popularity may only be due to the fact that he is the villain.
- Before James Garner was cast as Rourke, other actors considered for the role included Tommy Lee Jones, Jack Davenport, Kurt Russell, Heath Ledger, Josh Brolin and Joaquin Phoenix.
- On one of the earlier versions of the script, during the final battle, when Rourke uses the fire axe in order to kill Milo and accidentally breaks the glass window from the steel container where Kida is, instead of trying to swing the axe once more against him, Rourke would have pulled out a revolver and try to shoot Milo on the head, upon which Milo would have shoved the piece of the crystallized glass in the revolver's barrel, making the firearm explode and backfire. The shards created by the explosion would have hit Rourke in the eyes, rendering him blind and prompting him to fall from the balloon to his death. The writers decided to rewrite the scene, as they thought it was too similar to Helga's death.
- Rourke is the second Disney Villain to have one part of a book that the hero has, and the part the villain have has something important and use it for their own nefarious plans, Rourke has a page of the Shepherd's Journal from Milo Thatch which contains information about the Heart of Atlantis, the first is The Bookman from Bedknobs and Broomsticks has the part of The Spells of Astoroth from Miss Eglantine Price for the Substitutiary Locomotion spell and the third is Mittington Random in the Phineas and Ferb episode "The Klimpaloon Ultimatum" having the second journal of the Klimpaloon from Phineas and Ferb which contains the map to Klimpaloon.
- Like Wilhelmina Packard, Milo Thatch, and Kida, Rourke has his only appearance in House of Mouse. Strangely enough, he, for some reason, does not appear in the show's tie-in film Mickey's House of Villains, not even as a cameo, and is, therefore, one of the very few Disney villains featured on that show that doesn't appear in that film at all.
- During his final moments, Eddie Carr's scream during the latter's final moments in The Lost World: Jurassic Park is used twice, during Rourke's crystallization as he screams in pain and when he screams in fright before he is blasted to pieces by the propellers of the burning Gyro-Evac.
- Rourke's scoffing of Milo's objections against taking the Heart as pure rigid academics is rather true in real life: it is no good to be successful only at education institutions (such as achieving a CGPA of 4.0) if a person is not good at internships or has failed to secure a lifetime career. It is better to have a better working experience than to perform better academically.