Steve Zahn as Frank Heffley (Greg's dad)
Where You've Seen Him: As a costume-making bank robber in the 1999 indie gem Happy, Texas, as a wise-cracking sidekick in National Security, as a wise-cracking sidekick in Daddy Day Care (2003), and as a wise-cracking sidekick in the flaming wreckage called Sahara (2005).
Casting Grade: Greg's pop strikes us as a humorless, dour dad with possible anger and rage issues. While Zahn has recently branched out into drama (Rescue Dawn, A Perfect Getaway) he is, at his core, a comedian in a role without jokes.
Rachael Harris as Susan Heffley (Greg's Mom)
Where You've Seen Her: Most famously as the "controlling bitch" girlfriend to the Ed Helms character in the 2009 comedy smash The Hangover. Also, as Shanna in the hit TV show Cougar Town. Prior to that you had to look closely for her in roles like "skanky broad" in Hostage: A Love Story (2009) and "art opening spectator" in The Surrogate (2009). She's also been in ads for Dinty Moore Beef Stew and Geico, and was a correspondent on The Daily Show.
Casting Grade: Susan Heffley is a witty, mischievous mom, and by the looks of the line-drawn illustrations, also a bit of a hottie. How she ended up with Frank is anyone's guess, but the comedienne Harris seems very well-suited to nail the role.
Zachary Gordon as Greg
Where You've Seen Him: Primarily on TV (How I Met Your Mother, 24), and as the voice of Baby Melman in Madagascar: Escape 2 Africa (2008). His limited big-screen roles include "Kid #6 in Jump-Jump" in Four Christmases (2008) and "Young Bloom" in The Brothers Bloom (2008). This is Zachary Gordon's big break.
Casting Grade: As we've previously noted, Zachary Gordon looks to be a dead-ringer for the role of a charmingly dorky middle-school kid because the 11-year-old plays one in real life.
Devon Bostick as Rodrick (Greg's Brother)
Where You've Seen Him: As "Brent" in the recently released Saw VI, and as the lead character the Atom Egoyan-directed movie Adoration (2008) that was seen by about 13 people ($293K box office). This is another big opportunity for a young actor.
Casting Grade: Typically coiffed more shaggily than the buzz-cut Rodrick depicted in the books, Bostick is sufficiently menacing-looking as the archetypal mean older brother. He also passes the test as the archetypal skinny rock-n-roller wannabee and drummer in the high school band Löded Diper.
Chloe Moretz as Angie
Where You've Seen Her: As little Chelsea Lutz, one of the family members terrorized by demonic forces in the 2005 remake of The Amityville Horror, and also small TV roles in My Name is Earl and Desperate Housewives.
Casting Grade: Incomplete. OK, we know Diary of a Wimpy Kid is written at a 5th-grade reading level, but did we miss all the parts with Angie? Who is she? A new character added to appeal to a wider demographic? Got it, Hollywood.
Robert Capron as Rowley (Greg's best friend)
Where You've Seen Him: You probably haven't, unless you were paying very close attention during Bride Wars (2009) and noticed him as "Student #2."
Casting Grade: The cherubic Capron isn't exactly what came to mind when we thought of Rowley, but he seems passable as Greg's amiable, dim-witted sidekick and best friend.
Grayson Russell as Fregley (Weird neighborhood kid)
Where You've Seen Him: As "Texas Ranger," Ricky Bobby's trash-talking son in Talladega Nights (2006). You may recall him absolutely stealing the dinner table scene, telling his grandpa, "Chip, I am going to come at you like a spider monkey!"
Casting Grade: Take one look at Fregley, one look at Grayson Russell, and you immediately conclude he was born to play this role.
Connor and Owen Fielding as Manny (Greg's little brother)
Where You've Seen Them: Nowhere
Casting Grade: Fans of the series can't imagine a movie without Greg's cute, tattle-tale little brother Manny, and we were initially worried that's what we were going to get. Thankfully, his appearance in the trailer, played by twins Connor and Owen Fielding, erased those fears.