Harvey's mascot is "Joker," a harlequin jack-in-the-box character reminiscent of the mascot/logo for Paramount Pictures/Famous Studios' Noveltoons series of animated cartoons of the 1940s-1960s.

Harvey Comics started out as a conventional comic book publisher. It published comic books that featured a combination of characters it inherited from Brookwood Publications, licensed characters such as the Green Hornet and Joe Palooka and its own original characters.

But the company ultimately became best-known for characters it published from 1960s onward, characters are Casper the Friendly Ghost, Baby Huey, Herman and Katnip, Little Audrey, Tommy Tortoise and Moe Hare, and characters from Modern Madcaps. These characters originated as licensed properties, having been created by the Famous Studios animation studio, a division of Paramount Pictures, in the late-1940s and early 1950s. Harvey published several successful comic books based upon the Famous characters, and also developed original properties such as Richie Rich and Little Dot.

Harvey also licensed popular characters from newspaper comic strips, such as Mutt and Jeff and Sad Sack. While the company tried to diversify the comics it published (with brief forays in the 50s and 60s into superhero, suspense, horror, western and the like under their Thrill Adventure and Harvey Thriller line), kid comics were the bulk of their output.

In 1959, Harvey purchased the entire Famous line (including character rights and rights to the cartoon shorts). The Famous cartoons were repackaged and distributed to television as Harveytoons, and Harvey continued production on new comics and a handful of new cartoons produced for television. Casper the Friendly Ghost, who had been Famous' most popular original character, now became Harvey's top draw. Associated characters such as Spooky the Tuff Little Ghost, The Ghostly Trio, Casper's horse Nightmare, Hot Stuff the Little Devil, and Wendy the Good Little Witch were added to the Harvey line.

Due to a declining children's comics market, Harvey ceased publishing in 1982 (and founder Alfred Harvey retired).

In the summer of 1984, Steve Geppi (owner of Diamond Comic Distributors and Geppi's Comic World) paid $50,000 for, among other properties, Harvey's entire archive of original art from the Harvey comic Sad Sack. Geppi made this agreement with Steve Harvey, who at the time was President of Harvey Publications, Inc., as well as President of Sad Sack, Inc., a wholly owned subsidiary of Harvey Publications, Inc.

Meanwhile, with Harvey no longer publishing, Marvel Comics showed interest in licensing some of Harvey's properties. When nothing came of it, in 1985 the Marvel imprint Star Comics published a title called Royal Roy. Harvey sued Star for copyright infringement, claiming that Roy was a blatant copy of Richie Rich. (Veteran Harvey writer/artist Lennie Herman had created Royal Roy for Star Comics. Herman died in 1983 before the first issue of Royal Roy was published.) The Royal Roy comic ended after six issues and the lawsuit was dropped.

In 1986 Harvey resumed publication under the leadership of Alan Harvey (Alfred's oldest son), focusing on a few core titles, digests, and reprints.

In 1987 Harvey sued Columbia Pictures, for $50 million, claiming that the iconic Ghostbusters logo used in the blockbuster 1984 film was too reminiscent of Fatso from the Casper series. The court ruled in Columbia's favor, due to Harvey's failure to renew the copyrights on early Casper stories and the "limited ways to draw a figure of a cartoon ghost."