Born and raised in Los Angeles and later Orange County, California, Jimenez moved to New York City to attend college at the School of Visual Arts, where he now teaches a life drawing course as part of the undergraduate cartooning program. He began working at DC Comics when he was 21; his first published work was four pages in the DC miniseries War of the Gods (1991). Jimenez came out as gay in 1992, and his first open relationship was with the man who hired him at DC that same year, Neal Pozner.
He is probably better known for his work as writer/artist on Wonder Woman (2000-2003), main penciller of the miniseries crossover event Infinite Crisis (2005-2006), and his collaborations with writer Grant Morrison on New X-Men and The Invisibles.
His realistic and richly detailed art style is heavily influenced by the work of artist George Prez, who worked on 80's series such as The New Teen Titans (also as co-plotter), Crisis on Infinite Earths and Wonder Woman (also as writer). In fact, a large part of Phil Jimenez' work is also related to these three works by Perez: Jimenez has worked repeatedly in several Titans-related series (some issues of the ongoing series New Titans and Team Titans, and the miniseries JLA/Titans, The Return of Donna Troy and Tempest), was the main artist of Infinite Crisis, a sequel of Crisis on Infinite Earths and highly related to the historical limited series, and did a large run as writer & artist of Wonder Woman (as did Perez in the 80's). Jimenez and Perez also have worked together in 2005-2006 in the miniseries Infinite Crisis (where Jimenez was the main penciller, and Perez drew some sequences and covers for the series) and DC Special: The Return of Donna Troy (written by Jimenez and inked by Perez).
It was announced at the 2007 San Diego ComicCon that Jimenez had signed an exclusive contract with Marvel Comics. He will be one of the four artists to be working on Marvel's flagship title, The Amazing Spider-Man, the company's sole Spider-Man title, in which Marvel upped its frequency of publication to three issues monthly, and inaugurated the series with the "back to basics" story arc "Brand New Day" at the beginning of 2008. His first work on Spider-Man was in the Free Comic Book Day 2007: Spider-Man #1 (June 2007) comic book, with writer Dan Slott, which served as a prelude to Brand New Day. Phil Jimenez is currently the artist on Astonishing X-Men.