She has been an editor for Viz Media, working on over 20 manga series including Naruto, One Piece, Inuyasha and Case Closed. She has contributed to many comics, cartoons and manga publications including Animerica, Nickelodeon Magazine, Otaku United States of America and websites Anime News Network, The Comics Journal. Garrity was one of the most prominent cartoonists in the Modern Tales network of commercial webcomic sites, and served as the site"s editor from 2006 to 2012 In addition to writing and drawing Narbonic, she wrote (and often drew) spinoff series Li"l Mell and Sergio for Girlamatic, wrote Smithson (drawn by Brian Moore, Robert T Stevenson and Roger Langridge) for Webcomics Nation and is currently working on the comic Skin Horse which she illustrates and co-authors with Jeffrey Channing Wells.
She wrote a column called "All the Comics in the World" for comiXology.com from 2007 to 2012, and currently writes a webcomic review column called Number One Knows You"re A Dog for The Comics Journal.
She created the webcomic Smithson, with art by Robert Stevenson, Brian Moore, and Roger Langridge. The strip was first called More Fun and premiered in September 2003 as one of the original strips on the subscription-based site Graphic Smash.
The strip, which makes some use of infinite canvas techniques, follows the exploits of the self-appointed campus superhero, Chamucka Manitoba, and several students who attend Smithson College. In 2005, More Fun moved to Webcomics Nation under the new name Smithson.
She has also written for Marvel Comics, including their 2005-2007 Marvel Holiday Specials.
In 2010, Garrity contributed the story "Prison Knife Fight" to the Machine of Death anthology. She had additional prose stories published over the next two years, and joined the Science Fiction Writers of America in 2012. She has worked for Viz Media since 2000, serving as a manga editor since 2003.
Garrity has contributed to the magazine Otaku United States of America and reviewed manga for Jason Thompson"s Manga: The Complete Guide.
She appeared in Adventures Into Digital Comics, a 2006 documentary on the comics industry and Stripped, a 2014 feature-length documentary on comic strips. In 1997, Jeff Smith announced a contest in the letters page of his comic book series Bone inviting readers to name the baby rat creature who featured prominently in the then-current storyline.