"The Juror #6 Job" guest-stars Lauren Holly and Brent Spiner, with a cameo by ArminShimerman. Also, that particular episode, as well as others in the show, was directed by Jonathan Frakes, who has a brief cameo in "The Twelve Step Job."
There's also "The Snow Job," which reunites Christian Kane with fellow Angel evil lawyer alum Sam Anderson, as well as Danny Strong from Buffy the Vampire Slayer. Not to mention Mark Sheppard popping up all over the place.
British viewers might recognise Gina Bellman from Coupling, and a handful of people might notice that Aldis Hodge played Voodoo Tatum in Friday Night Lights. Or recognize him as Jake, the soldier who killed Sam from Supernatural.
How I Met Your Mother fans might recognize Beth Reisgraf as Works-With-Carlos Girl from Season 1.
WilWheaton in "The Two Live Crew Job". Especially hilarious given his character's rivalry with Hardison, a known Star Trek fan.
Hardison: The CIA computer guys call him the Kobayashi Maru.
Lampshaded in "The 12-Step Job" when Nate refers to an old gentleman in his rehab group as Nick Nolte. Uncredited, unconfirmed, but if it's not him, then it's a subversion rather than a lampshade, as none of the other cases are recognized.
Who also appeared on Next Gen (as the guy who kidnapped Data for his museum), and had a recurring character on Frasier (as Niles' lawyer, and later, Daphne's fiance).
D.B. Sweeney is Nate's priest friend in "The Miracle Job."
Quintessential "That Guy" Clancy Brown is the bad guy in "The Gone Fishin' Job." His appearance does raise the possibility that the entire Leverage universe is just part of Jack Shepard's purgatory.
Moreau, the Big Bad arms dealer the team is tracking in Season 3, turns out to be none other than Luka Kovac.
A few from "The Ten Li'l Grifters Job" - the mark is Mr. Matthews. His daughter is Jordan. The cop is Steven Flynn, who Firefly fans will recognize as the captain who attempts to steal Serenity in "Out of Gas."
Hey, look! Paul Kinsey is in "The 15 Minutes Job" and hasn't aged a day!
Roger Murtaugh is Charlie Lawson in "The Van Gogh Job." There's a lot of gamesmanship with the painting, but his character is too old for that shit.
Peter Stormare is the documentary filmmaker with the hots for Parker in "The Office Job."
Jimmy Ford, Nate's dad, is Top Gun's Viper.
Aunt Zelda is the target in "The Three Days of the Hunter Job."
Hey, It's That Voice!: If Jodi from the episode "The Future Job" sounds familiar to you, it's because she's portrayed by JenTaylor.
"The Wedding Job" has Nicole Sullivan, best known for her roles as Shego and Mira Nova.
If one listens closely then he/she can figure out that the prison head from "The Jailhouse Job" is Spy, though his voice is the same as when he played the helicopter pilot. By extension he's also the Pyro.
Irony as She Is Cast: Timothy Hutton, Academy Award winning actor, playing the character on the team who's the worst actor.
