Jason's height is 5'9" (1.75m).
Jason is often called by his nicknames Jase and Jasonic.
Jason is seen using his finger during the videos for the songs One, King Nothing and Nothing Else Matters.
In the film Some Kind of Monster, Jason claimed that he left Metallica because of James Hetfield's controlling desire to keep everyone in Metallica and out of side projects.
Jason co-wrote the song 'Blackened' on the album ...And Justice for All.
Jason went to Gull Lake High School in Richland, Michigan.
Jason has played in the bands Flotsam and Jetsam, Metallica, Voivod, and Rock Star Supernova.
Jason's official debut with Metallica was the album ...And Justice for All.
Jason uses a four-string bass.
Jason uses a pick when playing the bass.
After leaving Metallica, he played bass for Ozzy Osbourne.
Jason: I'll be right there (at the concerts) cheering them on.
(About replacing Cliff Burton)
Jason:I always felt this shadow cast over me, and I always felt like I wore shoes that were too large for my feet whenever I remember who I replaced.