[11] Starlin took over as plotter the following issue, and began developing an elaborate story arc centered on the villainous Thanos which spread across a number of Marvel titles.

Starlin also drew "The Secret of Skull River", inked by frequent collaborator Al Milgrom, for Savage Tales #5 (July 1974).

Starlin then took over the title Warlock,[15] starring a genetically engineered being created by Stan Lee and Jack Kirby in the 1960s and re-imagined by Roy Thomas and Gil Kane in the 1970s as a Jesus Christ-like figure on an alternate Earth.

Envisioning the character as philosophical and existentially tortured, Starlin wrote and drew a complex space opera with theological and psychological themes.

Warlock confronted the militaristic Universal Church of Truth, eventually revealed to be created and led by an evil evolution of his future–past self, known as Magus.

"[16] In Fall 1978,[17] Starlin, Howard Chaykin, Walt Simonson, and Val Mayerik formed Upstart Associates, a shared studio space on West 29th Street in New York City.

[20] The new decade found Starlin creating an expansive story titled "the Metamorphosis Odyssey", which introduced the character of Vanth Dreadstar in Epic Illustrated #3.

From its beginning in Epic Illustrated, the initial story was painted in monochromatic grays, eventually added to with other tones, and finally becoming full color.

[29][Note 1] Starlin and Bernie Wrightson produced Heroes for Hope, a 1985 one-shot designed to raise money for African famine relief and recovery.

[9][31] Starlin became the writer of Batman, and one of his first storylines for the title was "Ten Nights of The Beast"[32] in issues #417–420 (March – June 1988) which introduced the KGBeast.

[35] The death was decided by fans, as DC Comics set up a hotline for readers to vote on as to whether or not Jason Todd should survive a potentially fatal situation.

[9] Back at Marvel, Starlin began scripting a revival of the Silver Surfer series and introduced his creation Thanos into the story, which led to The Infinity Gauntlet miniseries and its crossover storyline.

[9] Starlin then worked for independent companies, creating Cosmic Guard (later renamed Kid Cosmos) published by Devil's Due and then Dynamite Entertainment in 2006.

[40] In 2007–2008, he worked on the DC miniseries Death of the New Gods[41] and Rann-Thanagar Holy War,[9] as well as a Hawkman tie-in which altered the character's origins.