Scott Mosier

On Smith's first feature film, Clerks, Mosier recorded the original sound on set, edited the film (at RST Video), and contributed to the budget. He also contributed by appearing on-screen as multiple characters, including the angry hockey player and Willam Black (Snowball).

On 1995 film Mallrats, Mosier worked in organizing the budget along with line producer Laura Greenlee, while presiding over a much larger crew. In the film, he portrayed Svenning's assistant, Roddy. The character later appeared on a Jay and Silent Bob MTV short.

On the 1997 romantic comedy film Chasing Amy, Mosier and Smith agreed with Miramax's Harvey Weinstein and Bob Weinstein to shrink the initial proposed budget from $3 million to $250,000. The compromise allowed Mosier and Kevin to cast their friends instead of established stars. Mosier appears in the beginning of the film as the comics convention patron who gets into an argument with Banky Edwards (Jason Lee) after demeaning his career as a tracer.

On the 1999 film Dogma, Mosier worked with Greenlee again; the editing of the film lasted nearly a year. He also played the Smooching Seaman who Ben Affleck and Matt Damon meet on the bus.

On the 2001 film Jay and Silent Bob Strike Back, Mosier worked with a budget of $20 million. The editing was difficult, due to the MPAA threatening to give the film an NC-17 rating. In the film, Mosier played the assistant director on the set of the fictional sequel to Good Will Hunting and reprises his Willam Black character from Clerks.

Mosier had a comparatively larger budget to work with on the film Jersey Girl, at $35 million. The editing was also difficult due to the studio's desire to cut a large amount of Jennifer Lopez footage with Ben Affleck following the poor box-office performance of Gigli.

Mosier produced Clerks II in 2006. Smith stated he edited the film himself, making Clerks II one of three films Mosier has produced with Smith, but not edited (the others being Mallrats and Zack and Miri Make a Porno). Mosier makes a brief cameo as a concerned father who shields his daughter's eyes from the sight of a character sitting on a toilet.

In 2008, Mosier worked again with Smith as the producer on Zack and Miri Make a Porno.

Mosier served as an executive producer, editor, and actor for Bryan Johnson's Vulgar, an Askew production. He had also served as a producer (along with Smith) on Drawing Flies, A Better Place, and Clerks: The Animated Series; he served as a co-executive producer on Good Will Hunting and Big Helium Dog. He also appeared in cameos in Drawing Flies as the Crying Diaperman, in A Better Place as Larry, and in Vulgar as Scotty. Although he barely recorded any episodes in 2017, Mosier is also a co-host, along with Smith, of the SModcast podcast hosted by the Smith-owned SModcast.com.

In 2007, Salim Baba, a short documentary Mosier produced, was nominated for an Academy Award. Filmmakers Tim Sternberg and Francisco Bello received the nomination (Mosier was unable to be nominated due to a limit of two nominees per short film).[3]

On SModcast 77, Mosier announced he would not produce Smith's film Cop Out (2010), instead pursuing his directorial debut.[4] He stated on SModcast 90 that he finished writing his first feature screenplay and was in the process of trying to sell it.[5]

On August 10, 2011, Mosier stated on Twitter that he has written some episodes of the Ultimate Spider-Man cartoon on Disney. This was confirmed in a special "SModcast Extra" (attached to SModcast No. 204 and episode 5 of the Comic Book Men podcast "Secret Stash") in which he and Smith interview Joe Casey; Mosier has written six scripts for the series.[6][7]

Mosier made his directorial debut with Illumination Entertainment's animated feature The Grinch, based on the book by Dr. Seuss, and co-directed with Yarrow Cheney. It was released on November 9, 2018.