Mike, a bass guitarist and vocalist, worked at the Beatles' "Apple Studios", where his love for music grew stronger after some memorable sessions with several famous singers. He also joined a band, Gold, who, despite having few hits, sold a number of singles such as "Stay with Me My Love" and "Paradise".
At some point Mike and Junior Campbell signed to the same publisher and their partnership sparked. They have collaborated on writing television jingles, which continued even after leaving their bands.
Mike lives in Surrey with his wife Barbera, daughter Sian and son Ben.
- Thomas' Anthem (with footage from series 3 only)
- I'm Thomas the Tank Engine (Japan only; Thomas and the U.K. Trip)
- Thomas' Anthem (with footage from series 1-4)
- Let's Have a Race
- Gone Fishing
- Don't Judge a Book By its Cover
- The Island Song
- Really Useful Engine
- Rules and Regulations
- That's What Friends Are for
- Thomas' Christmas Song
- It's Great to be an Engine
- Sir Topham Hatt
- Accidents Will Happen
- Night Train
- The Snow Song
- Harold the Helicopter
- Donald's Duck
- Percy's Seaside Trip
- Every Cloud has a Silver Lining
- Come for the Ride
- James the Really Splendid Engine
- Little Engines
- Down by the Docks
- Winter Wonderland
- Boo! Boo! Choo-Choo
- Never, Never, Never Give Up
- Five New Engines in the Shed
- The Red Balloon
- There Once Was an Engine Who Ran Away
- Troublesome Trucks
- The Whistle Song
- Mike O'Donnell has said that he does not have a favourite song from the show due to each song having their own charm.
- In his youth, Mike was brought up on Tom & Jerry and The Flintstones, as well as Harman & Ising.
- Mike does not know how to read sheet music.
- Both Mike and Junior had started coming up with music ideas for the eighth series, before it was revealed they were not to return.
- Sometimes on his YouTube channel, Mike releases re-recordings of certain characters themes or songs.
- He used the beat for Mean Mr. Mustard by the Beatles as an inspiration for the original theme tune in hopes of having Ringo sing an extended near-three minute rendition with lyrics.
- Contrary to popular belief, he and Junior did not compose the jingle for The Britt Allcroft Company logo.