In Doug Dimmadome's first appearance, he appears at the end of the episode when his son, Dale Dimmadome, drinks magic lemonade which grants his wish to be reunited with his father. As a reward for finding his long lost son, Doug Dimmadome gets Timmy Turner and his pals a spot into Dimmadome to see Crash Nebula on Ice, although they are forced to hand out concessions.
Doug Dimmadome is the owner of a construction company in this episode with the goal of tearing down Dimmsdale Flats and replacing it with a strip mall. Mr. Turner opposes this, but without the deed to the Flats, he cannot stop Dimmadome or his workers. Timmy travels back in time to retrieve the deed, but his father ends up selling it to Doug Dimmadome anyway for chump change, and he proceeds with his plans to tear down the Flats.
After Vicky sells a prized Striker Z not even belonging to her to Mr. Turner, Doug Dimmadome approaches her and offers her a much better price after Mr. Turner drives off. Vicky steals the car back from Mr. Turner, and brings it to Doug Dimmadome's Precariously Perched Cliff-side Estate, but before she can sell it to him, the car is pushed over a cliff and destroyed, leaving Vicky's attempt for a deal "Dimmadone".
Timmy Turner joins the Dimmsdale Ballhogs to pay for a replacement V-Cube after his melted, and finds out the team is owned by Doug Dimmadome, who wants to move them to Alaska. Timmy helps lead Doug Dimmadome's team to victory, although Dimmadome seemed disappointed as he had bought a lot of "blubber nuggets".
When Timmy "runs away" from home by travelling into television, Mr. and Mrs. Turner seek the help of Doug Dimmadome after being led to his Cable Station by Tootie, but he is of little help to them as he rambles to himself on whether or not he likes Timmy, based on past experiences with Timmy outlined in the above episodes. Mr. and Mrs. Turner use his equipment anyway to broadcast a message to Timmy inside television. It reaches him, and Timmy exits the TV universe into the cable station, reuniting with his family, but Doug Dimmadome comes to the conclusion that Timmy is a menace to him, and has them all thrown out of his building by security.
Doug Dimmadome's latest enterprise is a planned community near Dimmsdale called Dimmadome Acres. Everything seems quaint and normal inside, but everyone acts eerily similar and in a trance like state. Timmy, the only one not drinking the locally produced milk due to his practicing for a belching contest, investigates and finds out that the milk is being produced in a factory underneath the town by Dimmadome, who explains to Timmy that the milk is genetically modified to enslave the townspeoples' minds into living in his suburbanite planned communities, making him more money. Timmy foils Doug Dimmadome's plan by throwing magic soda he was drinking earlier into a giant tank of milk to cause the milk to become fizzy and explode. The magic soda/milk flows out of the factory and into the community, turning it back into a woodland forest, and wiping everyone's memory, including Doug Dimmadome who is then pushed away by a deer driving a bulldozer.
Doug Dimmadome funds Mr. Crocker's webshow after it begins to become wildly popular due to Crocker getting mauled by monsters from inside Timmy's house. Crocker is given a studio and lots of money, but is required to be constantly beat up by monsters. Timmy allows Crocker to be beaten for a while, then wishes the monsters away, causing Doug Dimmadome to immediately cancel Crocker's show and take his money back.
Doug Dimmadome himself does not appear, but Dark Laser disguises himself as him at the beginning to the episode to fool the Turner family into thinking they won a contest to be launched into space. His clothes are colored wrong and patched together, and he does not respond to "Doug Dimmadome?" with his catchphrase "Yes, Doug Dimmadome!".