[4] Heck learned art through correspondence courses as well as at Woodrow Wilson Vocational High School in Jamaica and at a community college in Brooklyn.

[5] He continued with an impromptu art education in December 1949[6] when at the recommendation of a college friend he landed a job at Harvey Comics.

There he repurposed newspaper comic strip Photostats into comic-book form – including the work of Heck's idol, famed cartoonist Milton Caniff.

Heck remained at Harvey, where one co-worker in the production department was future comics artist Pete Morisi,[5] for two-and-a-half years.

[5] For publisher U.S. Pictorial in 1955, he drew the one-shot Captain Gallant of the Foreign Legion, a TV tie-in comic based on the 1955–57 syndicated, live-action kids' show of that name.

As Heck recalled Pete Morisi, who worked at Media at the same time [I did], had been to Stan Lee's office, and he had brought his [art portfolio].

In the years immediately preceding the arrival of the Fantastic Four, Spider-Man, and the other popular heroes of Marvel's ascendancy, Heck gave atmospheric rendering to numerous science fiction / fantasy stories in that comic as well as in sister publications Strange Tales, Tales to Astonish, Strange Worlds, World of Fantasy, and Journey into Mystery.

"[5] During the period fans and historians call the Silver Age of Comic Books, Iron Man premiered in Tales of Suspense #39 (March 1963) as a collaboration among editor and story-plotter Lee, scriptwriter Larry Lieber, story-artist Heck, and Kirby, who provided the cover pencils and designed the first Iron Man armor.

He came up with the initial look of Iron Man's armor ...[16]Heck himself recalled in 1985 that while some sources claimed then "that Jack Kirby did breakdowns," ...that's not true.

[17] Hawkeye, Marvel's archer supreme, first appeared in Tales of Suspense #57 (Sept. 1964),[18] following the introduction of femme fatale Communist spy and future superheroine and S.H.I.E.L.D.

He successfully made this adjustment, and went on to make The Avengers, which he drew through issue #40 (May 1967), plus the 1967 annual, one of his signature series.

Heck would return to The Avengers one final time to co-plot and pencil issue #45, with inks by Vince Colletta.

[citation needed] By 1970, however, Marvel work became less frequent, and Heck obtained assignments from rival DC Comics, beginning with a short story in the supernatural anthology House of Secrets #85 (May 1970).

He did his first DC superhero work with The Flash #198 (June 1970), illustrating a backup story of the super-speedster, and eventually garnered additional work including romance comics, and the backup features "Batgirl" and "Jason Bard"[29] in Detective Comics, and "Rose and the Thorn" in Superman's Girl Friend, Lois Lane.

[30] He began a short run on Wonder Woman with issue #204 (Feb. 1973), in which the character's powers and traditional costume were restored after several years,[31] and he also freelanced for the short-lived publisher Skywald Comics.

[8] Heck still occasionally worked at Marvel, penciling the odd issue of Daredevil, Sub-Mariner, Ghost Rider, The Avengers and others in the mid-1970s.

[32] Writer Tony Isabella and Heck launched the new superhero team book The Champions in October 1975.

"[9] With writer Gerry Conway, Heck co-created the DC cyborg hero Steel, the Indestructible Man in the premiere issue (March 1978) of the titular comic.

[36] After that series' cancellation, Heck became regular artist on The Flash, and in 1982 reunited with Conway to draw the Justice League of America, including that year's crossover with the All-Star Squadron.

Fortunately, as he proved first with Iron Man and then with the Avengers, Don could rise to the occasion because he had real talent and a good grounding in the fundamentals.