The captain, as his name indicates, is the head of Corona's royal guard. As such, he spends a majority of his time working to ensure the safety within the kingdom remains intact. At some point in time, the captain came to adopt an orphaned girl named Cassandra, whom he raised from childhood as his daughter.
The captain is gruff and no-nonsense, with a strict sense of order. He does not tolerate any criminals within the kingdom, and will go on an endless pursuit to apprehend those who offend Corona's crown. He tends to view criminals as worthless and pathetic, and understandably refuses to show even the slightest bit of sympathy or kindness toward them, as seen in his relationship with his arch-rival, Flynn Rider. Even after Flynn proved his selflessness by rescuing Corona's lost princess, Rapunzel, the captain refuses to welcome him into the castle with open arms. Instead, he chose to ruin Rider's life whenever the chance came his way, even if it meant going against common decency and fairness, showing a bitter and spiteful side to himself.
However, the captain is not as cruel as he may seem; he is able to show humility and admit when he may have overreacted, though he is a man who will stand by his decisions for the most part. He is also loving and protective toward his daughter, Cassandra. According to Cassandra, the captain raised her to be strong, independent, and taught her the importance of earning your goals through hard work. He also appears to have a soft spot for Maximus, whom he interacts with in an extremely friendly and jovial manner, a side of the captain that is practically never seen elsewhere. Maximus is also the only character that the captain appears to genuinely respect, outside the royal family.
The captain is the head of the palace guards who currently spends most of his time chasing after Flynn Rider and the Stabbington Brothers. Eventually the brothers are arrested but Flynn is still on the move. Accompanying him is his guards and horse Maximus who may actually have more intellect. Throughout the film he and his men chase Flynn and later Rapunzel. Soon enough after returning to the palace, they find Rider and arrest him. When taking him to execution he escapes with the help of the infamous Pub Thugs and in during which, the captain is knocked out by Attila the thug. He is not seen for the remainder of the film and the finale shows that Maximus has taken over his captain status.
The captain plays a minor role in the sequel, taking place six months after the events of Tangled, and before Rapunzel and Eugene's wedding in Tangled: Before Ever After. He retains his position as captain of the guard, and is first seen chasing down Rapunzel and Flynn (now going by his true name, Eugene) as they pursue the kingdom's border wall to allow Rapunzel a chance to look out into the land surrounding Corona. The captain fails to stop them, once again, but simply accepts defeat and calls Rapunzel back once preparations for her coronation are set to begin. Later on, the captain is seen ensuring King Frederic that Corona's security has been amped, per request, although this does not stop the pirate Lady Caine and her band of thieves from crashing Rapunzel's coronation. The thieves barricade the hall's door, locking the guards out, though they manage to break through in time to arrest the villains, who were already defeated by Rapunzel, Eugene and Cassandra.
The captain plays a supporting role in the animated series. Due to being considerably more pessimistic, jaded and down-to-earth than the rest of the cast, the captain is often looked down upon as an antagonistic figure of sorts—specifically with Eugene, as the rivalry between himself and the captain remains, despite Eugene being a much-beloved resident of the castle's household. Examples of this are seen in "Fitzherbert P.I.", where Eugene pursues a position in the royal guard, prompting the captain to sabotage Eugene's chances of earning the job, and "Big Brothers of Corona", where the captain was against the idea of hiring Eugene's former partner, Lance Strongbow, as a much-needed guard instructor. Despite his firm stance on situations, the captain has shown that his mind can be changed, and he will begrudgingly own up to his wrong doings, if any.
His relationship with Cassandra is also touched upon; the episode "Great Expotations" revealed that the captain has reservations about granting Cassandra a portion on the guard, despite believing her to be more than qualified for the job. She manages to prove her worth after assisting the young alchemist, Varian, in saving the castle, though she would continue to make efforts to highlight her capabilities. In "Under Raps", Cassandra lured a separatist into Corona to uncover the reasoning behind his fascination with an ancient journal that belonged to one of Corona's previous kings. As revealed to Rapunzel, part of her reason for doing so was to prove herself to her father.