Matthew Mercer

Critical Role Mercer at the 2023 Critical Role live show in Wembley Arena. Mercer is the Dungeon Master of the web series Critical Role, which launched on Geek & Sundry in 2015, where he leads several other voice actors through a Dungeons & Dragons campaign. Critical Role was both the Webby Winner and the People's Voice Winner in the "Games (Video Series & Channels)" category at the 2019 Webby Awards; the show was also both a Finalist and the Audience Honor Winner in the "Games" category at the 2019 Shorty Awards. After becoming hugely successful, the Critical Role cast left the Geek & Sundry network in early 2019 and set up their own production company, Critical Role Productions; Mercer is the company's chief creative officer. This feat went on to set a Guinness World Record for the most-funded TV series project in Kickstarter's history. Mercer reprised his role as Sylas Briarwood and other characters.

Luke Winkie, in a human-interest story for Slate, called Mercer "an expert improviser" and "a maestro with the dice in his hands, weaving interlocking plot lines and complex thematic threads out of thin air" with "the innate ability to make a Dungeons & Dragons campaign feel like a tightly wound limited drama". Winkie commented that "it can be downright intimidating to watch Mercer when he's at the peak of his powers. As a career voice actor, he possesses all of the subtle performance intangibles that saturate his storytelling with life: the timing, the verve, the language flourishes". They analyzed nineteen characters based on exceeding a threshold of minimum voice time and plot relevance and determined through "holistic analysis of voice quality" of these characters that "breathiness" in Mercer's voice "emerged as signalling positive morality and stances of safety, comfort, and trust, where whisperiness signals negative morality and stances of threat. Qualitatively, pitch dynamism was also found to correlate with morality and stancetaking: the more limited the pitch dynamism, the more likely it is that the character portrayed is an Enemy and that they adopt stances of threat". From June to August 2021, Mercer appeared on Exandria Unlimited, a spinoff of Critical Role, as a player. In March 2022, he reprised his role in the two part special Exandria Unlimited: Kymal. In 2025, he was the game master for the Age of Umbra limited series. In August 2025, Critical Role announced that Brennan Lee Mulligan would take over as Game Master from Mercer for their fourth campaign, which premiered on October 2, 2025; Mercer appears in the campaign as a player. Rolling Stone stated that "the inclusion of Mulligan is huge, but not entirely surprising" given Mulligan's background as "a well-established Game Master" along with previous comments made by Mercer on eventually shifting "into a 'Professor X' role as a mentor to the next generation of storytellers rather than remaining the face of the brand in perpetuity".

Game design Hayley McCullough, for American Journalism, commented that "Mercer is well-known for his homebrew mechanics, character classes, and feats". Mercer's work as Dungeon Master has led to the development of three campaign setting books being published about his world of Exandria. The first is the Critical Role: Tal'Dorei Campaign Setting (2017) published through Green Ronin Publishing. The second is the Explorer's Guide to Wildemount (2020) published through Wizards of the Coast, thus making Exandria an official Dungeons & Dragons campaign setting. The third is Tal'Dorei Campaign Setting Reborn (2022), a revised and expanded edition of the Tal'Dorei Campaign Setting, which was published by Darrington Press, the publishing label created by Critical Role Productions. Tal'Dorei Campaign Setting Reborn was nominated for the 2022 ENNIE Awards in the "Best Setting" category.

On March 15, 2022, a new adventure module titled Critical Role: Call of the Netherdeep (2022), with Mercer, James Haeck, and Chris Perkins as lead designers, was released. It is the second collaboration book between Wizards of the Coast and Critical Role Productions. Mercer was then a consultant on the Dungeon Master's Guide (2024) for the revised 5th Edition of Dungeons & Dragons. Mercer was a designer on Daggerheart (2025), a tabletop role-playing game system by Darrington Press, and created the "Age of Umbra" campaign frame for the system. The video of his proposal became popular among fans as it involved an escape room game he secretly created with the Critical Role cast as a surprise for Ray. They have a pet corgi named Omar. Their pet green-cheeked conure, Dagon, died in December 2021.

Mercer said in 2017 that, while he is heterosexual, he has also been attracted to men in the past and experienced homophobia while growing up as a boy who liked to experiment with an androgynous appearance. He explained that he tries his best in storytelling to also represent the experiences of close LGBT family and friends. In 2018, he revealed that he suffers from body dysmorphic disorder and has always struggled with his physical appearance. Tal'Dorei Campaign Setting Reborn (lead designer, Darrington Press, 2022) Critical Role: Call of the Netherdeep (project lead, Wizards of the Coast, 2022)