The comic has received mixed reactions over the years on its inclusion of topics such as race, feminism, politics and sexism.

[2] In 2009, Ishida said he wanted to create comics after reading a Peanuts paperback as a child, due to "the simplicity and solitary nature of the medium.

[4][3][a] In 2000, Ishida taught himself HTML, put together a Geocities web page, and started uploading Sinfest strips seven days per week.

"[5] Ishida, who lives a private life and has little interaction with his readership,[6] has said that Sinfest has included political views that have led to reader complaints since its early comics.

[8] Paste magazine described it as a four-panel comic strip relying on pop culture references and dark humor.

His side-kick was it girl Monique,[11][2] Garrity describes her as a "sexy coffeehouse poet" and recounts her spending "one of her earliest strips in a bikini, showing her ass to the reader".

"[6] In 2011, Ishida started to produce weekly strips in color on Sundays, giving readers, in his words, "something extra fun and engaging".

[7] Over its first decade as a webcomic it evolved into a more serious work, with a large cast of regular characters commenting on such themes as organized religion,[18] American exceptionalism,[9] and economic insecurity.

[8] Garrity said in 2012 that "raunchy strips about strippers are followed by cute cat-and-dog gags are followed by religious humor are followed by autobio strips are followed by shit-stirring political cartoons are followed by spoken-word poetry are followed by lessons in drawing Japanese kanji, one of Sinfest’s signature running features", and that "Sinfest is always, first and foremost, about what Ishida wants to cartoon at any given moment.

[21][non-primary source needed] In December 2022, Ishida wrote that he was banned from Patreon for promoting "sentiments of discrimination based on gender identity or sexual orientation";[22][23] he had started the "sinfest" account on January 8, 2018.