For the first seven seasons of MST3K, Beaulieu operated and voiced the Crow T. Robot puppet. He also helped designed the various film sets and played the role of Dr. Clayton Forrester, who was the head mad scientist, or "mad", for the first seven seasons. Initially Dr. Forrester was assisted by Dr. Laurence Erhardt. His second assistant was TV's Frank. Following the departure of Frank at the end of the sixth season, Mary Jo Pehl joined the cast in his place, playing Forrester's mother Pearl. At the end of the seventh season, Trace left the series.
Pehl's Pearl Forrester character replaced him as the head "mad" and Bill Corbett took over the voicing and operation of Crow.
According to a 1999 Satellite News interview, Trace's least favorite movie he had to endure on the show was The Incredible Melting Man. In a 2014 interview with Spreaker.com, Trace later confirmed that The Unearthly was also one of his least favorite movies to experience during the show's run and also commented on the fact that the the most painful films ended up being the funniest due to the crew having to actually suffer through them.
Trace appeared as a semi-regular in Freaks and Geeks as the school's biology teacher, Mr. Lacovara. He also appeared in The West Wing episode "Bad Moon Rising". For several years, Trace was a writer for America's Funniest Home Videos. In 2002 he was the head writer, producer, and host of the pilot episode of the show People Traps for the Animal Planet network. Outside of acting, Trace also wrote the script for the one-shot comic book Here Come The Big People published by Event Comics.
Trace released a illustrated book entitled Silly Rhymes For Belligerent Children, which features off-color poetry, among other things.
Trace joined many of his former castmates as a regular performer for Cinematic Titanic.
In fall of 2014, Trace directed and appeared as mad Frankenstein-esque scientist in the music video comedy short The Frank along with other MST3k members.
In 2015, Trace provided the voice of the robot Art for the webseries Other Space. This role reunited him with Joel Hodgson.
In 2016, Beaulieu co-created the half-hour comedy series Renfest, which also featured Mary Jo Pehl and Dave (Gruber) Allen. He also began co-hosting the movie-themed podcast Movie Sign with the Mads, along with Frank Conniff and Carolina Hidalgo.
Trace and Frank appeared at the RiffTrax Mystery Science Theater 3000 Reunion live event in 2016 and the 2017 Summer Shorts Spectacular. They also contributed to the tag-team RiffTrax of Batman v Superman: Dawn of Justice in 2017.
- TV's Madam (voice) - Cave Dwellers
- Jackie Mason jar (voice) - The Unearthly
- Winston Churchill (voice) - The Dead Talk Back
- "In the first season on KTMA we basically went in cold without watching the films. If you look at those episodes, they’re real hit-or-miss. It was just off the top of our heads."
- "Our budget for the show was microscopic. I think Josh and I were pulling down $25 a show, and I think Joel’s budget was a little higher, because he had to build props. We thought, well, let’s see how far this goes. We didn’t really know how long the show would last or if anyone was even watching it."
- "Then we put the station’s phone number up on the screen and started getting feedback. That’s when we realized, hey, there’s more than just four or five people watching this."
- "Since Joel’s character created the robots, his relationship with them was kind of parental. Then when Mike’s character came in, it was a completely different dynamic. He had to keep those guys in line, but he was also one of the gang. The onscreen persona was like a pizza restaurant manager who’s only like maybe a couple of months older than the staff is."
- "One of the most frustrating things for me was finally realizing that all we were going to produce out of Best Brains was Mystery Science. We had such a beautiful environment, we had our own studio, our own production facility, we had a shop, we could build anything, we had the talented people. But the way it was structured, from a business standpoint, it was just impossible to produce anything else and be fair to everyone involved. Jim Mallon was going to own any new show produced. And that didn’t really sit well with a lot of us."
- "The younger generation is full of riffers."
- (on the distribution of Cinematic Titanic) "This is the one we've been to the most. This is our third year. This one fits our sensibility more because our MO has always been do-it-yourself, and this one is all that. It's really people-powered. Comic-Con is really just Hollywood blowing you away with how much money it has and awing you with its giant displays and you really are, as a fan or an observer, you're really put in this category. Here it really just, like, flows everywhere. You just can see people being creative and kind of doing their own thing. I think this one fits much better, I prefer this con way more than Comic-Con."
- (on the difference between geeks and nerds) "Geek is more intense than nerd."
- (on researching infamous filmmakers for the show) "Yeah, it's information I’d like to get rid of. This was long before you could go to the Internet and look up anything, so we were really shooting in the dark to get these movies to use on the show. We didn't know who Coleman Francis was. We were aware of some of the more prominent [B-movie] directors, like Ray Dennis Steckler (Wild Guitar), Russ Meyer (Beyond the Valley of the Dolls) and Ted V. Mikels (The Corpse Grinders)."
- (on psychotronic movie research) "Yeah, Michael Weldon's 'The Psychotronic Video Guide' was our bible. We sat on the floor and read it to each other for a week. We’d circle movies we thought sounded good -- ‘Oh, we want this one!’ -- thinking we could just submit this list to the Comedy Channel and they'd get them for us. But the reality was they’d send us a big box of tapes and we'd just sort through them. We thought we could say, “Well, we like these two . . . these over here are great . . . ” But then they would come back to us and say, “Well, you've got to take these three, and these other two that you don’t like,” because they were all from distributor licensing agreements. And sometimes the ones we didn't request were the most painful and probably made the best episodes . . . because we were actually living the pain."
- (on the most painful movie he watched on the show) "The Un- . . . something. The Unearthly? I think maybe that was the title. It was this black and white, boring, awful movie. That and . . . The Melting Man? ... I couldn't remember if he was incredible, or amazing, or colossal. That one is so bleak! By the time we get to the end where he’s melting to nothing next to a garbage can, I thought, "Yes, that’s how I feel right now. I feel that uplifted."
- (on stand-up life in Minneapolis) "Yeah, in the ‘80s anyone could do stand-up. It wasn't hard to get into. I only did it a couple of years, and then 'Mystery Science' took off and that really met all of my creative needs. So I didn't really go out on the road much after that. But Frank still does stand-up."
- (on puppeteering) "I’d done a little bit. I’d done some puppets in school but never as intently as we did on the show. Joel developed the puppets’ first versions, and then we worked together to add some stuff to them as the show went on. Each puppeteer took their puppet and made it their own. We’d do our own maintenance and stuff. It’s like when the army gives you a gun, and that's your gun. You name it. You maintain it."
- (on the set design work he did for the show) "The initial sets, Joel and I built, and then Jeff Maynard and Patrick Brantseg came on board and they kind of took it to another level. Their talent and professionalism was unsurpassed. The idea for the look of the set was [the 1972 science fiction movie] Silent Running -- the bio-pods from that movie and even the idea of a guy marooned in space with two robots -- that’s what happened to Bruce Dern in the film. Also, we all liked to make stuff, so it was fun for us. I’d always wanted to make a spaceship for a movie and I got to do that [for 1996’s big-screen feature Mystery Science Theater 3000: The Movie]."
- (if he could give the MST3k treatment to any movie if he didn't need a licensing fee) "I don’t really have one, but Josh... always cites Life Is Beautiful. ... And I’d never seen it before so I decided to watch it, and you know what? He was right! I was stunned! It's terrible, and there's so much to make fun of. I do like bad movies. I have a fondness for them, and right now I’m finding that I love Netflix because they've got so many bad movies for streaming. Netflix right now is sort of like that bad VHS store every neighborhood used to have. You've watched all the good stuff so you find yourself going through the back catalog of a lot of people’s so-called careers. In fact I just watched Solar Crises. It’s an early ‘90s forgotten sci-fi movie. And it’s kind of epic. It stars Charlton Heston, Tim Matheson, Jack Palance . . . and it’s stunningly bad. The special effects are awesome, but the movie . . . it’s got a great pedigree. But my poodle has a great pedigree and it still craps everywhere. . . . I actually don’t have a poodle. I lie. I lie for the joke." 
- 2012 Trace Beaulieu interview for MentalFloss.com
- 2014 interview on Spreaker.com
- WIRED Magazine|Mystery Science Theater 3000: The Definitive Oral History of a TV Masterpiece
- 2010 CNN Interview with CT gang
- 2007 FRED Entertainment Interview
- Trace Beaulieu's 2015 interview on his Kickstarter-funded puppet show program Vermin
- Diffuser 2014 interview