- "You'll find that a lot of engines run on Sodor thanks to his expertise."
- ―Hank, Perhaps He's Got a Corset
Gregory Larson is a renowned technician who currently serves as chief engineer at Crovan's Gate Works.
Gregory Larson is a mechanical genius, known for his major accomplishments in machine and locomotive repairs. His notable accomplishments include Greg and Lars, Hank, and many other engines looking for a second chance. He lives at Bluebell Manor near the Skarloey Railway, where he works on personal projects with his close friend Paul the Mechanic. Gregory was seen watching Molly and Rheneas talk about Young Tucker's bad luck. On another occasion he was seen playing his guitar and watching Den and BoCo on the Crater Lake bridge. Mr. Larson is good friends with the Thin Controller, often engaging in fencing matches. He was also present when the Thin Controller confided to his engines his love for adventure.
He was recently appointed as the new chief engineer of Crovan's Gate Works. After said promotion, he was accompanied by Paul the Mechanic to meet with Sir Robert Norramby at Barry Island Scrapyards to visit a prospective project.
Larson was supervising Donald and Douglas' overhaul, when Edward comes to check in on the twin's progress. He casually strums his guitar as he usually does, until Douglas begins to disparage diesels, which causes him to stop playing.
Gregory Larson is completely mute, and does not speak. He is able to communicate with his closest friends by strumming a few chords on his guitar. He is good friends with The Thin Controller, Rick Shay, Weaver, and Vegard.
Mr. Larson is close with Paul the Mechanic, who is always read to lend a wrench to Larson's latest project.
- Season 1: Snow Blind (remastered version only), Scruff's Scaffolding (cameo), Greg and Lars (mentioned)
- Season 2: Young Tucker (cameo), Swan Dive (cameo), All the World's a Stage (cameo), Swashbuckler
- Season 3: Perhaps He's Got a Corset, Samson, BoCo, and the Man in the Hills (cameo), Culdee Fell, Penn Pals (cameo), Ice Breaker (indirectly mentioned)
- Web Clips: Paul the Mechanic - Meet the Characters!