Scruff was brought to Sodor to work at Whiff's Waste Dump. He cannot stand being cleaned and when Thomas once tried to have him cleaned, he fled and hid in a siding until he was coaxed out with the promise of being allowed to shunt rubbish trucks. He once had to go to the Sodor Steamworks to have his "scruncher" mended and later that day, he helped Gordon tidy up the waste dump before the inspector arrived.
Scruff once had to be repainted and he enjoyed his new look so much that he did not want to get dirty. He then went round the Island, looking for a new job, until Gordon reminded him that he was most useful at the rubbish dump with Whiff.
In the eighteenth season, Scruff broke down at Crocks Scrap Yard. So Samson shunted him to the Steamworks. After he was fixed, he overheard the Fat Controller saying Samson had taken his car to the scrapyards and Scruff told the Fat Controller he knew a shortcut. He then made it to the scrapyards just before Reg could grab it.
Scruff, alongside the other engines wanted to participate in the Great Railway Show, though the Fat Controller did not select him.
Scruff is a grimy little chap, with a lime green boxy shape. He likes to sometimes get dirty during his job. He is more than content with "scrunching" and shunting garbage wagons at Whiff's waste dump and has few other aspirations. He has been known to run in fear and hide away from things that he does not quite understand and can find having all the focus on him a little daunting. It seems, at times, that Scruff would rather be busily working in the background. However, he is cheerful to welcome engines to the waste dump and happy to have others join in with the "scrunching". He is notably, perhaps, one of the few engines on Sodor with little desire to be clean and presentable. Scruff's main motivator is being able to just get stuck in and knuckle down with his jobs.
Scruff is based on No. 9369 "Musketeer", a Sentinel 100 HP BE Type chain-driven vertical-boiler steam locomotive built in 1946 by Sentinel Waggon Works. "Musketeer" is preserved by the Northamptonshire Ironstone Railway Trust.
Scruff is painted lime green with dark green stripes, funnel and front. He has brass nameplates on either side of his tanks, although his name is only written on these in merchandise. In the television series, the plates are completely blank.
- Matt Wilkinson (UK; fourteenth season onwards, excluding The Great Race singing voice)
- Kerry Shale (US; fourteenth season onwards - UK; The Great Race singing voice only)
- Jesse Grimm (Germany; fourteenth season onwards)
- Kōtarō Nishiyama (Japan; fourteenth season onwards, excluding The Great Race)
- Nozomu Sasaki (Japan; The Great Race only)
- Carlos Íñigo (Latin America; fourteenth - eighteenth season)
- Ernesto Lezama (Latin America; nineteenth season only)
- Christian Greger Strøm (Norway; fourteenth - seventeenth season)
- Jarosław Domin (Poland; fourteenth season onwards)
- Jorge Teixeira (Spain; fourteenth season onwards)
- Denis Bespalyy (Russia; seventeenth season onwards)
- Kari Tamminen (Finland; fourteenth season onwards)
- Haris Grigoropoulos (Greece)
- During his first appearance in Thomas and Scruff, Scruff did not have a rear coupling hook in the fourteenth season, yet he was seen pulling wagons. As of the seventeenth season, he now has a rear coupling hook.
- For some unknown reason, Scruff's nameplates have always been blank in the television series but not on his merchandise.
- In the twentieth season, Scruff gained lamps and brakepipes on his front and rear.
- His side tanks are considerably taller than his basis to accommodate his face.
- Scruff travels far faster in the television series than his basis is capable of.
- “I'd rather be a really useful engine, than a really shiny engine any day.”
- ―Scruff, Scruff's Makeover, seventeenth season
- Wooden Railway
- Mega Bloks (discontinued)
- Capsule Plarail
- Classic Minis
- Old School Minis
- DC Super Friends Minis (as The Atom and Armor Batman)
- Space Minis
- Neon Glow in the Dark Minis
- Beach Minis
- Collectible Railway
- Adventures (sold only in Clean-Up Crew 4-Pack)