During the harbor Day festival he sang a song of how the inhabitants of Danville drove out a giant shark that had terrorized them by eating teachers and politicians in the 1700s. Upon seeing the giant robot shark built by Phineas and Ferb, Candace took Stacy with her and got into a boat with Captain Squint to chase the mechanical shark in order to try and bust her brothers. Phineas and Ferb, not seeing it's Candace and believing that the reenactment had begun, decided to run from them.
Captain Squint used rubber duck to help track down the shark, and used a toilet plunger to capture it but the robot shark swallows him. The boys offer cheese and sausage (which he had used as bait). However, he declines and remarks that he "thought the stomach of a shark would be a little more, stomachy."
The shark eventually washes up on land due to Candace and Stacy's pursuit. Captain Squint disembarks from the shark, thanking Phineas and Ferb for the new rocket-propelled leg they built and quickly leaves ("The Belly of the Beast").
In Spain he is named "Capitán Pata-Palo" (Captain stick-leg)
He may have diabetes as he said an octopus ate his pancreas, though it could be a fisherman's tale.
Captain Squint is a reference to Captain Quint from Jaws.