These include Demolition Hammer's Epidemic of Violence, The Jacksons' Victory; Sepultura's Beneath the Remains, Arise, Chaos A.D. and Roots; Soulfly's Dark Ages; Obituary's Cause of Death; and every album by the Elric-influenced metal band Cirith Ungol.

"[8] After graduating from San José State University in 1973 with a BA in Painting (as a "President's Scholar"), Whelan studied at the Art Center College of Design in Pasadena, California for nine months from 1973 to 1974.

Donald A. Wollheim of DAW Books gave him his first American professional assignment—the cover painting and frontispiece drawing for Lin Carter's fantasy novel, The Enchantress of World's End (May 1975).

[2] Shortly after arriving on the East Coast he exhibited some of his student work in the Lunacon convention art show in New York, where it was seen by Harlan Ellison.

In 1975, Whelan painted the cover illustrations for ten books, eight from DAW and two Ace reprints of early Darkover novels by Marion Zimmer Bradley.

[2] Whelan soon gained a reputation as a talented, imaginative, and dependable cover artist, working for science fiction and fantasy publishers such as DAW, Del Rey, and Ace.

Whelan credits the 1978 publication of Anne McCaffrey's best-selling The White Dragon featuring his cover art as a turning point in his career.

[8] Fantasist Michael Moorcock wrote of Whelan, "I am more than usually grateful for an artist who not only depicts him [Elric] as I imagine (and describe him) but who also manages to capture some of the appropriate atmosphere" (Wonderworks, p. 36).

Science fiction writer Anne McCaffrey praised him, declaring, "Fortunate indeed is the author who has Michael Whelan for an illustrator" (Wonderworks, p. 55).

Whelan has returned to illustrate several major book covers during his semi-retirement, including the last book of Stephen King's Dark Tower series, the final volume of Robert Jordan's The Wheel of Time, covers for The Last King of Osten Ard series by Tad Williams, and the first arc of The Stormlight Archive by Brandon Sanderson.