 | Will Smith Captain Steve Hiller |
 | Bill Pullman President Thomas J. Whitmore |
 | Jeff Goldblum David Levinson |
 | Mary McDonnell First Lady Marilyn Whitmore |
 | Judd Hirsch Julius Levinson |
 | Robert Loggia General William Gray, Chairman Joint Chiefs |
 | Randy Quaid Russell Casse |
 | Margaret Colin Constance Spano, White House Communications Director |
 | Vivica A. Fox Jasmine Dubrow |
 | James Rebhorn Albert Nimzicki, Secretary of Defense |
 | Harvey Fierstein Marty Gilbert |
 | Adam Baldwin Major Mitchell |
 | Brent Spiner Dr. Brakish Okun |
 | James Duval Miguel Casse |
 | Lisa Jakub Alicia Casse |
 | Giuseppe Andrews Troy Casse |
 | Ross Bagley Dylan Dubrow |
 | Bill Smitrovich Lt. Colonel Watson |
 | Mae Whitman Patricia Whitmore |
 | Harry Connick Jr. Captain Jimmy "Raven" Wilder |
 | Kiersten Warren Tiffany |
 | John Storey Dr. Isaacs |
 | Frank Novak Teddy |
 | Devon Gummersall Philip |
 | Leland Orser Tech / Medical Assistant #1 |
 | Mirron E. Willis Presidential Aide |
 | Ross Lacy Presidential Aide |
 | David Pressman Alex, Presidential Aide |
 | Vivian Palermo Tech / Medical Assistant #2 |
 | Raphael Sbarge Captain, Chief Ground Controller |
 | Bobby Hosea Major Danowitz (according to credits) (Col. Harper according to what's onscreen) |
 | Dan Lauria Commanding Officer, Space Command |
 | Steve Giannelli Commander, USS Georgia (listed in credits as Radar Technician) |
 | Carlos Lacamara El Toro Radar Operator |
 | John Bennett Perry Secret Service Agent |
| Troy Willis Secret Service Agent |
 | Tim Kelleher Senior Airman, Ground Controller |
 | Wayne Wilderson Area 51 Technician |
 | Jay Acovone Area 51 Gate Guard |
 | James Wong SETI Technician #1 |
 | Thom Barry SETI Technician #2 |
 | Jana Marie Hupp SETI Technician #3 |
 | Matt Pashkow Second Officer in Space Command (Major Danowitz according to script) |
 | Robert Pine Glenn Parness, White House Chief of Staff |
 | Marisa Johnston Co-Worker #2 (as Marisa Morell) |
 | Michael Winther Co-Worker #3 |
 | Dexter Warren Co-Worker #4 |
| Paul LeClair Co-Worker #5 |
| Michael Vacca Lieutenant Peterson |
 | David Chanel Secret Service Agent |
 | John Capodice Mario |
 | Greg Collins Military Aide |
 | Derek Webster Sky Crane Pilot |
 | Mark Fite Marine Fighter Pilot |
| Eric Neal Newman Pilot |
 | Levan Uchaneishvili Russian Pilot |
 | Kristof Konrad Russian Pilot |
 | Kevin Sifuentes Tank Commander |
 | Elston Ridgle Soldier Guarding Helicopter |
 | Randy Oglesby Mike Dodge |
 | Jack Moore Stoney Jackson |
 | Barry Del Sherman Street Preacher |
 | Lyman Ward Secret Service Agent |
 | Anthony Crivello Lincoln |
| Richard Speight Jr. Ed |
 | Barbara Beck Monica Soloway |
 | Joe Fowler Reporter |
| Andrew Warne Reporter |
| Sharon Tay Reporter |
| Peter J. Lucas Russian Reporter (as Peter Jozef Lucas) |
| Yelena Danova Russian Newscaster |
| Johnny Kim Korean Newscaster (as Derek Kim) |
 | Vanessa J. Wells Newscaster |
 | Gary W. Cruz Carlos Ortiz, LA Newscaster |
 | Ron Pitts Video Newscaster |
 | Wendy L. Walsh Herself |
| Christine Devine Video Newscaster |
 | Mark Thompson Video Newscaster |
| Ernie Anastos Rex Black, New York Newscaster |
 | Kevin Cooney Commander-in-Chief, US Atlantic Command |
 | Rance Howard Chaplain |
 | Nelson Mashita Japanese Technician |
 | Jeff Phillips B-2 Pilot |
 | Sayed Badreya Iraqi Pilot |
 | Adam Tomei Sonarman, USS Georgia |
 | John Bradley Lucas |
 | Kimberly Beck Housewife |
 | Thomas F. Duffy Lieutenant |
 | Andrew Keegan Older Boy |
 | Jon Matthews Thomson |
 | Jim Piddock Reginald |
| Frederic W. Barnes Himself (as Fred Barnes) |
 | Eleanor Clift Herself |
 | Jerry Dunphy Himself |
| Jack Germond Himself |
 | Morton Kondracke Himself |
 | John McLaughlin Himself |
| Barry Nolan Himself |
| George Putnam Himself |
| Eric Michael Zee Northridge Field Reporter |
 | Pat Skipper Redneck |
| Carlos Lara Farmer Kid |
| Mike Monteleone Butler |
| Lee Strauss Elvis Fanatic |
| Lisa Star Woman on Roof |
 | Malcolm Danare Intellectual on Roof |
| Arthur Brooks Trucker on Roof |
| Michael Moertl Thief |
| James J. Joyce Master Chief Petty Officer |
| Joyce Cohen Kim Peters |
 | Julie Moran Herself - "Entertainment Tonight" Reporter |
| Robin Groth Flagstaff News Anchor |
| Richard Pachorek LAPD Helicopter Pilot |
 | Gary A. Hecker Alien Vocal Effects (as Gary Hecker) |
 | Frank Welker Special Vocal Effects |
| Jonathan Adler Secret Service Agent (uncredited) |
 | Erick Avari SETI Chief (uncredited) |
 | Greg Bronson Police Officer at White House (uncredited) |
| Dean Devlin Eagle 2 Pilot (uncredited) |
| Daren Dochterman British News Translator (uncredited) |
 | Volker Engel Man in Office (uncredited) |
 | Bob Friend Himself - "Sky News" Anchorman (uncredited) |
| Jeffrey Gold German Fighter Pilot (uncredited) |
| Michael Haddad Trailer Trash (uncredited) |
| Lincoln D. Hiatt Colin Barclay (uncredited) |
| Jonathan Khan Pilot (uncredited) |
| Darin Mangan Staff Sergeant (uncredited) |
 | Scott McKinley Joint Chiefs of Staff (uncredited) |
| Bryan D. Moss Israeli Fighter Pilot (uncredited) |
| Roy Newton Pilot (uncredited) |
| Gary Pike Helicopter Passenger (uncredited) |
| Darla Rae Protestor - Omni Hotel (uncredited) |
 | Nectar Rose Stripper (uncredited) |
| Bonnie Silco Bride (uncredited) |
 | Tadao Tomomatsu Big Hat Guy on Tower (uncredited) |
| Michael A. Valenzano Young Pilot (uncredited) |
 | Tracey Walter Area 51 Lab Technician (uncredited) |
 | James With British Pilot (uncredited) |
| James Woodson Pilot (uncredited) |
 | Dakota Boomer |
 | Unknown 22068-2 AWACS Pilot |
 | Unknown 22068-3 Area 51 Gate Guard #2 |
 | Unknown 22068-4 Asian Pilot |
 | The White House The White House |
 | World Trade Center World Trade Center |