Paris Cullins had sent DC Comics samples of his fledgling comics art since 1976, finally meeting with art director Dick Giordano in the last week of 1979. Cullins recalled in 2007 that,
I brought new pages and he loved it. The pages were Batman vs. Manhunter. I did it on a lark. He then told me, ...'Come in the first day after New Year's and Ill have a script for you, and talk to you about the [DC intern] program'. I came in on January 2nd and he gave me a script that day. ... When I started with them they had me doing some horror stories ... I also did one feature in particular, called 'I, Vampire'.
Cullins' first known credited comics work was as penciler-inker of the six-page story "Mystic Murder", by writer Steve Skeates, in the DC Comics supernatural anthology Secrets of Haunted House #42 (Nov. 1981). Cullins went on to pencil stories in such similar DC titles as House of Mystery, Ghosts, The Unexpected and Weird War Tales through the early 1980s, and made his superhero debut penciling an eight-page "Tales of the Green Lantern Corps" backup feature in Green Lantern #154 (July 1982). As well, artist Ernie Colon, whom Cullins met at DC and who drew Richie Rich and other children's titles for Harvey Comics, "offered me a job doing some extra work for Harvey Comics. For several months I drew Richie Rich and Hot Stuff.
After co-penciling Justice League of America #212 (March 1983) with Rich Buckler, and making his cover debuts with The Daring New Adventures of Supergirl #7 and penciling first full-length comic, Blue Devil #1 (June 1984), starring a superhero he had co-created with writer Gary Cohn and Dan Mishkin earlier that month for a backup feature in The Fury of Firestorm #24 (June 1984).
Blue Devil ran 31 issues, through cover-date December 1986, with Cullins penciling the first six and Blue Devil Annual #1 (1985), and covers through the end of the run. Cullins additionally drew dozens of DC covers and occasional stories through the decade, and numerous character pages for Who's Who: The Definitive Directory of the DC Universe. Cullins and writer Len Wein helped introduce the Ted Kord Blue Beetle to DC, which had acquired that character from the defunct Charlton Comics, teaming on the 1986 Blue Beetle series. Cullins penciled issues #1-9, 11-14, and 17-18 (collectively, June 1986 - Nov. 1987).
Cullins broke into Marvel Comics penciling a six-page High Evolutionary story each in the 1988 X-Factor Annual #3 and Silver Surfer Annual #1, though still freelancing primarily for DC collaborating there with writer J.M. DeMatteis on a revival of Jack Kirby's The Forever People, penciling stories and covers for a six-issue miniseries (Feb.-July 1988). With writer Mark Evanier, primarily, Cullins co-plotted and penciled issues #1-9, 11-12, and 15-18 (collectively, Feb. 1989 - July 1990) of a revival of Kirby's The New Gods.
n the 1990s, Cullins, while keeping DC as his home base, branched out to draw additional occasional comics for Marvel, and for publishers including Acclaim Comics, Massive Comics Group, Penthouse Comics, and Crusade Comics. Teamed with writer Fred Burke, Cullins penciled stories and covers for all nine issues of the superhero-team comic Hyperkind, for Marvel's Clive Barker-created Razorline imprint.
Largely absent from comics from 1996, when he did pencil-breakdowns for DC's Life, The Universe and Everything #1, to 2001, when he penciled the cover of DC/Onstar's Onstar Batman Special Edition #1, Cullins contributed a one-page Blazing Glory pinup to Atomeka Press' A1 Sketchbook (Nov. 2004), his last known comics work as of 2007.
At some point, Cullins did book-cover art and "worked for advertisement agencies, and did storyboards for [video]games and TV commercials, Activision in particular, and full-color storyboards and designs for a game called Terror in the Bermuda Triangle".
In December 2006, the Philadelphia, Pennsylvania-based Maximum Overtime Media announced the first-quarter 2007 planned premiere of Gritz n' Gravy, "a quarterly illustrated adult urban fantasy and popular-culture national magazine", with Cullins, a company co-founder, announced as publisher.