McNeil's chief work is the ongoing science fiction comic series Finder, which she has self-published since 1996 and has been available as a webcomic since 2005.

She has written and illustrated comics for anthologies including Dignifying Science and Smut Peddler. She worked as an illustrator on the Oni Press series Queen & Country in 2003 and supplied art for the Avatar Comics' one-shot, Frank Ironwine in 2004. She also provided a two-page guest-illustrator spot for Transmetropolitan: Filth of the City. She is editor in chief and print manager of Saucy Goose Press, which produces Smut Peddler and other related projects. Her adaptation of D. J. MacHale's first Pendragon book, The Merchant of Death, was released on May 20, 2008.

In 1997, at Comic-Con International, McNeil won the Lulu Awards' Kimberly Yale Award for Best New Talent for her work on Finder and Shanda the Panda. McNeil also won the Ignatz Award for Promising New Talent in 1998.

McNeil was nominated for Lulu Award Lulu of the Year in 2001 and 2002, and for an Ignatz Award for Outstanding Artist in 2001. Finder won the Ignatz for Outstanding Series in 2004 and 2005. Her work has been nominated for Eisner Awards in several categories over the years (including "Best Writer/Artist" in 2002 and 2003), and winning "Best Webcomic" for Finder in 2009.