A letterer is a member of a team of comic book creators responsible for drawing the comic book's text. The letterer's use of typefaces, calligraphy, letter size, and layout all contribute to the impact of the comic-book-reading experience. The letterer crafts the comic's "display lettering": the story's title lettering, creator credits, and any specialized captions that appear on the story's first page. They also craft the lettering that appears in the word balloons, also designing the various sound effects that appear within the comic book story. Many letterers also design logos for the comic book company's various titles.

By the time comic books came of age in the 1940s, the huge volume of work demanded by publishers had encouraged an assembly-line process, dividing the creative process into distinct tasks: writer, penciller, letterer, inker, and colorist. By the late 1940s, it became possible to make a living just lettering comic strips and comic books for artists, studios, and companies that did not have the time or desire to do it in-house. The career of freelance letterer was born, and by the 1950s, letterers such as Gaspar Saladino, Sam Rosen, and Ben Oda were crafting full-time careers as letterers for DC Comics, Marvel Comics, and King Features.

Letterer and logo designer Ira Schnapp defined the DC Comics look for nearly thirty years. Starting in 1940, he designed or refined such iconic logos as Action Comics, Superman, The Flash, and Justice League of America, while also creating the distinctive appearance of DC's house ads and promotions. (Schnapp also designed the Comics Code Authority seal, which was a fixture on comic book covers from all major companies for over forty years.)

DC Comics used a stable of more than 20 letterers in the comics they published in the 1950s and 1960s (some of the letterers — like Jerry Robinson and Dick Sprang — were more well known as artists):

Starting in around 1966, Ira Schnapp's classic, art deco-inspired look was replaced by the pulsing, organic style of Gaspar Saladino, who redesigned DC's house style for the counterculture era. Gaspar became the cover letterer for all of DC's books throughout the 1970s, and even "ghosted" as Marvel Comics' "page-one" letterer for much of the same period. Gaspar's work became so iconic that various independent comics publishers which sprang up in the 1970s and 1980s – such as Atlas/Seaboard, Continuity Comics, and Eclipse Comics – hired him to design logos for their entire line of titles.

From 1930 through the 1990s (with a few exceptions), the letterer added their lettering, in pen and ink, on the same original art page the penciler drew. The penciled art was then inked after the letterer had completed their work on the page. At DC Comics during the "Silver Age" of the 1960s, pencilers were required to "rough in balloons and sound effects" for the letterers to use as a working guide. An accomplished letterer was able to adapt his or her style to the style of the art for that particular book.

The evolution of desktop publishing powered by computers, especially those made by Apple, began in the 1980s, and started having a gradual impact on comics lettering soon after. One of the first users of computer-generated lettering was writer/artist John Byrne, who made fonts from existing lettering. (Incidentally, Byrne made use of existing lettering by other artists, such as Dave Gibbons, without their permission. Now Byrne uses a computer font based on the handwriting of letterer Jack Morelli – with Morelli's permission.) Other early users of computer lettering were David Cody Weiss and Roxanne Starr, who experimented in computer lettering with Bob Burden's Flaming Carrot Comics.

Computer lettering really started making an impact with the availability of the first commercial comic book font, "Whizbang" (created by Studio Daedalus) around 1990.