Known best for his portrayal of Jay, Silent Bob's hetero lifemate in such movies as Clerks, Mallrats, Chasing Amy, Dogma, and Jay and Silent Bob Strike Back, Jason Mewes was born June 12, 1974, in New Jersey. (See also Jay.)
According to IMDb.com, Jason graduated from Henry Hudson Regional High School sometime "around 1990." He met actor/director Kevin Smith (aka Silent Bob) when hanging out at the local recreation center. In An Evening With Kevin Smith, the filmmaker says that he knew Jay was someone interesting when, one day, he entered a room at the rec center and proceeded to fellate every phallic object within reach, completely oblivious to the reactions of those who were watching.
Besides his work in the Jersey Trilogy, Jason has also appeared in smaller, independent works such as Matt Gissing and Malcolm Ingram's films Drawing Flies (1996) and Tail Lights Fade (1999), Bryan Johnson's Vulgar (2000), and Mark Anthony Galluzzo's R.S.V.P. (2002). Jason has also had cameo appearances in Scream 3 (as Jay, from Jay and Silent Bob) and in An Evening with Kevin Smith (as himself).
Though he was straightedge (e.g. no drugs, no alcohol, etc.) for much of his life, Jason eventually abandoned that philosophy. Not too long afterward, he began showing noticeable signs of alcohol and drug abuse. On the Clerks DVD director's commentary, he was markedly intoxicated and/or high. In March 1999, he was arrested for heroin possession in Keansburg, New Jersey and pled guilty in February 2001, receiving a sentence of probation.
Disturbing-yet-fun fact about Jason Mewes:
Interestingly--and frighteningly--enough, a Jason Mewes porno apparently exists. According to Kevin Smith, Jason rigged a hidden camcorder to film him while he asked his then-girlfriend Jamie to marry him. After she said yes, they...ahem...got it on with the camera still rolling.
Mewes then showed the film to Kevin, who said it was "the worst amateur porn in the world." Apparently, the camera was set at such a position that it caught the reflection of the MTV Video Music Awards off an X-men poster, confusing the autofocus and causing it to focus back and forth between Jason's ass and the VMAs.
The video work was so terrible, Kevin described it as "like Clerks, but funnier." That, coupled with what Kevin dubbed Jay's "three thrusts, one tug, and you're on your way" method of lovemaking apparently made for a particularly poor pornographic experience.
Sources:
1. imdb.com
2. An Evening with Kevin Smith, Sony Pictures, 2002. (ISBN: 0-7678-9367-0)