Grant has a long history scripting for both major publishers such as Marvel Comics and DC, as well as smaller companies such as First Comics and Dark Horse.

Beginning in the early 1980s Grant wrote a number of works for Marvel. In addition to bringing the Punisher back into the forefront of the Marvel Universe after a several-year lull, Grant has written Avengers, The Hulk, The Defenders and fill-in runs on comics such as What If?, Spectacular Spider-Man, and Marvel Team-Up.

In the early 1980s his creator-owned character, the female ninja Whisper, debuted at Capital Comics though the company's publishing arm folded after only two issues (and a promotional poster) of the book were published. Several months after First Comics picked up two other Capital publications (Nexus and the Badger), they published a one-shot entitled Whisper Special which led to Whisper being featured in the anthology book First Adventures and eventually to her own ongoing series. During this time, Grant also wrote American Flagg! (he was personally selected by Howard Chaykin to take over scripting the book after Chaykin's departure), a fill-in run on Shatter, a short-lived book of his own creation called Psychoblast and a few issues of Classics Illustrated at First.

At Dark Horse Comics, Grant wrote several limited and ongoing series in the short-lived Dark Horse shared superhero continuity, including the entire two-year run of the series X.

Over the last several years, Grant has written numerous works for IDW Publishing including original comics featuring the characters from the television show CSI. He also wrote a one-shot about featuring an updated version of his character Whisper for Boom! Studios.

In addition to comic book work, Grant has written a number of novels for young adults under the pen-name Frank W. Dixon.

As of 2009, he writes the column "Permanent Damage" as a staff writer for the online magazine Comic Book Resources.

He lives in Henderson, Nevada and he is a self-described atheist.

• The Hardy Boys Casefiles (under the pen name Franklin W. Dixon)
• Cult of Crime (1987)
• The Crowning Terror (1987)
• Too Many Traitors (1988)
• Nightmare in Angel City (1988)
• Thick as Thieves (1989)
• Final Gambit (1992)

• Badlands (with Vince Giarrano, 5-issue mini-series, 2006, tpb, Dark Horse Comics, May 1993, ISBN 1878574531)

• Crime Scene Investigation:
• Secret Identity (with Steven Perkins and Gabriel Rodriguez, 5-issue mini-series, tpb, 2005, IDW Publishing, ISBN 1933239409)
• Dying in the Gutters (with Stephen Mooney, 5-issue mini-series, 2006, tpb, IDW Publishing, March 2007, ISBN 1600100481)

• The Safest Place (with co-author Victor Riches and art by Tom Mandrake, Image Comics, 2008)