Duff played rhythm guitar with Alice in Chains for a few shows after their reunion.
Duff sat right next to Kurt Cobain on a plane just days before Cobain's death. Cobain had just fled rehab in LA and was returning home to Seattle. Duff is one of the only people to have seen Cobain for sure after his escape.
On his wrist, Duff has a tattoo of the word "Grace," which is his daughter's name.
Duff has a finance degree from Seattle University.
Duff is color blind. This is believed to be the reason why he usually wears all black.
Although Duff is left-handed, he plays bass right-handed.
Duff studied martial arts with famous fighter Benny Urquidez.
In 1994, McKagan underwent emergency pancreas surgery after his pancreas exploded due to alchohol-induced pancreatitis.
Duff currently resides in Santa Monica, California.
At 6'3", Duff was the tallest member of Guns N Roses.
Duff nearly died in a skateboarding accident at age 12. He broke two vertebrae trying to grind a rail.
Duff's biggest idol is John Entwistle, the legendary bassist for The Who.
Duff has stated that he hates when Guns N Roses is referred to as a Glam Metal band.
It was Duff who invented the term "Sleaze Rock."
Duff preferred guitar when he was a teen, but he stuck to bass because it was clear that he was much more talented at it.
Duff was on lead vocals for a few tracks off of the GNR album The Spaghetti Incident.
Duff replaced original GNR bassist Ole Beich in 1985. Axl Rose and Izzy Stradlin were so impressed by McKagan that they called Beich on the spot and told him he was through.