Whilce Portacio was born July 8, 1963[7][8] in Sangley Point, Cavite City, Philippines. He grew up in places such as Midway Island and New Mexico before his family settled in San Diego, California. He began reading comic books at the age of ten, when his neighbor decided to get rid of her husband's collection, and through this, he discovered the work of creators such as Jack Kirby and Neal Adams, who were the two most important influences on Portacio's art. Though Portacio dreamed of becoming an astronaut, his height and eyesight did not meet the necessary requirements, which determined that art would be his vocation. In high school, he continued to create his comic books with his long-time friend, Scott Williams, who would one day be a prolific comic book inker in the industry.[8]
In 1992, Portacio left Marvel to co-found Image Comics with six other high-profile artists. He quickly withdrew from Image due to his sister's illness. He eventually published his title Wetworks through Jim Lee's Wildstorm imprint in 1994. Other notable series that Portacio worked on include Stone and Marvel's controversial Heroes Reborn storyline within Iron Man. At this time Portacio's artwork is notable for his impressive, action-packed splash pages with one character dominating the page borders.
In August 2000, Portacio fell into a diabetic coma as a result of a failing pancreas. He woke up a week later, thirty pounds lighter, and unable to walk, stand or even draw. Only six months later was he able to pick up a pencil and draw. According to his blog, "My mind could see what I wanted to draw but my hand couldn't accomplish it."[13]
In 2006, Portacio returned to his artistic duties at Wildstorm on Wetworks vol. 2, which was being written by Mike Carey. Portacio left the book with issue #6. He also began art duties on the monthly DC Comics series Batman Confidential.
On June 9, 2008, it was announced that Portacio would be the new artist on Spawn starting in October 2008 with issue #185, providing pencils with Spawn creator Todd McFarlane returning as co-writer with Brian Holguin as the new creative team.
Following his run on Spawn, he has done more work with Marvel. He contributed pencils to Hulk #18 in 2008[14] and had a run on The Uncanny X-Men.[15]
Two pages of Portacio and Arthur Adams' Longshot were up for auction in the 2021 April 1–4 Comics & Comic Art Signature Auction in Dallas, where the starting prices were $2,600 and $6,250, respectively.[16]
In July 2021, Marvel announced that Portacio was one of the various Asian artists for the book Marvel's Voices: Identity #1, in which he would contribute the art for the character Wave (Pearl Pangan).[17][18]