Will Smith Agent J Tommy Lee Jones Agent K Lara Flynn Boyle Serleena Rosario Dawson Laura Vasquez Johnny Knoxville Scrad / Charlie Rip Torn Chief Zed Tony Shalhoub Jeebs Patrick Warburton Agent T Jack Kehler Ben David Cross Newton Colombe Jacobsen-Derstine Hailey Peter Spellos Motorman Michael Rivkin Man with Dog Michael Bailey Smith Creepy Lenny Venito New York Guy Alpheus Merchant MIB Guard Jay Johnston Agent Joel McKinnon Miller Agent Derek Cecil Repairman Agent Peter Spruyt MIB Customs Agent Kevin Cotteleer MIB Customs Agent Marty Belafsky MIB Customs Agent Rick Baker MIB Passport Control Agent Martha Stewart Self Michael Jackson Agent M Sid Hillman Agent Gee Tom Whitenight Agent C Nick Cannon MIB Autopsy Agent Jeremy Howard Bird Guy Alien / Postal Sorting Alien Mary Stein Bird Lady Alien Martin Klebba Family Child Alien John Alexander Jarra / Family Dad Alien Ernie Grunwald Young Postal Employee Chloe Sonnenfeld Young Girl at the Post Office Doug Jones Joey Biz Markie Rapping Alien Kevin Grevioux Pineal Eye Derek Mears Mosh Tendrils Brad Abrell Mannix (voice) Rick Avery Subway Passenger (uncredited) Darrell Foster MIB Autopsy Agent (uncredited) Gene LeBell Subway Passenger (uncredited) Pete Macnamara Man in Black (uncredited) Bart Mixon Alien Puppeteer (uncredited) Thomas Rosales Jr. Subway Passenger (uncredited) Peter Siragusa Mayor of Grand Central Terminal Locker Aliens (voice) (uncredited) Brian Steele Sharkmouth (uncredited) Mark Steger Quadraped Alien (uncredited) Alan Tuskes Lobsterhead Alien (uncredited)