Flynn worked with Belle on the mainland before they came to Sodor. Belle suggested to the Fat Controller that Flynn be brought to Sodor to help her fight fires. Flynn had instantly become popular with the engines on Sodor. Later on, Flynn and Belle helped Percy save Thomas and Kevin from Den and Dart at the Sodor Dieselworks. Flynn also used his ladder to assist welders during the restoration of the Dieselworks.
Flynn usually runs on the rails despite being a road and rail vehicle. This was due to his wheels being nonoperational for a time. When they were repaired, he went on the roads and found himself wobbling all over the place, so he returned to the rails. However, after putting out a fire at a farmhouse, he regained his confidence in using the roads and was able to help Bertie and Butch.
Later, some railway inspectors questioned whether the Fat Controller really needed two fire engines. Since Belle beat him to emergencies twice in a row, Flynn decided that he was not useful and sulked in his shed while Belle kept guard at a fireworks display at Ulfstead Castle. At the rescue centre, Butch arrived, telling Flynn that there was a fire at Brendam Docks. Flynn put the fire out, knowing now that Sodor really does need two fire engines.
When the Search and Rescue Team was dispatched to save a stranded whale at Bluff's Cove, Flynn and Belle sprayed water on the stranded whale in an attempt to keep it wet.
Flynn is a "really red fire engine" who fights fires on Sodor and is part of the Sodor Search and Rescue team. He has both tyres and flanged wheels, meaning that he is capable of running on roads and on rails. Flynn is fast, fearless, and ready to fight any fire. He is popular with the engines and held in high regard all over Sodor, but his overly-enthusiastic bravado can lead to not listening to instructions amidst his racing about and result in him making mistakes. He can also be self-conscious about maintaining his fire-fighting hero status. Nevertheless, Belle and the rest of the Search and Rescue team are often there to support him and keep him on course. And, at the end of the day, Flynn always has it in him to prove that he is always ready to rescue, and is a really useful hero.
Flynn is a hybrid design based on Tatra, Oshkosh, and Latil fire rescue vehicles. However, he most likely resembles a 1964 Oshkosh W800 4X4 aircraft rescue fire engine.
Flynn is painted red with yellow lining, with the Sodor Search and Rescue Centre emblem on his cab doors in white.
- Season 15 - Wonky Whistle (cameo), Percy the Snowman (cameo), and Fiery Flynn
- Season 16 - Race to the Rescue and Welcome Stafford
- Season 17 - Too Many Fire Engines and The Frozen Turntable
- Season 18 - Millie and the Volcano (mentioned)
- Season 19 - Toad and the Whale, Wild Water Rescue (cameo) and Rocky Rescue
- 2011 - Flaming Flynn
- 2012 - Fiery Flynn!, The Fat Controller's Bedtime Story (Issue 639), and Welcome Stafford (cameo)
- 2013 - Toby to the Rescue and Too Many Fire Engines!
- 2014 - Frozen Turntable
- 2015 - Dusty Rusty (does not speak)
- Rupert Degas (UK/US; Day of the Diesels - sixteenth season)
- Ben Small (UK/US; seventeenth season only)
- Rob Rackstraw (UK/US; nineteenth season onwards, excluding Toad and the Whale)
- Glenn Wrage (UK/US; Toad and the Whale only)
- Tomohiro Tsuboi (Japan)
- Christoffer Staib (Norway; fifteenth - sixteenth season)
- Fredrik Paasche (Norway; Day of the Diesels onwards, excluding sixteenth season)
- Rainer Schmitt (Germany)
- Jacek Król (Poland)
- Armando Coria (Latin America)
- Bernard Demory (France and French speaking Canada)
- Miguel Ángel Poison (Spain)
- In several books, Flynn is depicted with blue wheel arches.
- Between the fifteenth and sixteenth seasons, Flynn's water cannons were operated mechanically. However from the seventeenth season onwards, his cannons are worked by the fire fighters, more accurately reflecting the operations of his basis.
- Flynn is presently the only character who can travel on both rail and road.
- Wooden Railway (two-pack with tanker; "Fiery Flynn"; two-pack with Butch as "Race to the Rescue")
- Motor Road and Rail (Asia only)
- Mega Bloks (discontinued)
- Wind-up (Japan only)
- Pocket Fantasy (discontinued)
- Boss (pullback; discontinued)
- Collectible Railway
- Motorized Railway
- Minis (Classics, Racers and DC Super Friends; coming soon)
- Thomas and Friends Adventures (coming soon)