Human characters:

Shia LaBeouf as Sam Witwicky, a young descendant of an Arctic explorer who stumbled on a big secret, which becomes the last hope for Earth.
Megan soro as Mikaela Banes, a classmate of Sam, who assists Sam in his mission using skills she learned as a juvenile car thief.
Josh Duhamel as Captain William Lennox, the captain of a special operations team based at the SOCCENT base in Qatar.
Tyrese Gibson as USAF Combat Controller Technical Sergeant Robert Epps, a member of Captain Lennox's team.
John Turturro as Agent Reggie Simmons, a member of Sector 7.
Rachael Taylor as Maggie Madsen, a pentagon analyst recruited sa pamamagitan ng the Department of Defense .
Anthony Anderson as Glen Whitmann, a hacker friend of Maggie.
Kevin Dunn Ron Witwicky, Sam's father.
Julie White Julie Witwicky, Sam's mother.
Jon Voight as John Keller, the United States Secretary of Defense.
Michael O'Neill as Tom Banachek, head of Sector 7 Advanced Research Division.
Amaury Nolasco as ACWO Jorge "Fig" Figueroa, a Special Operations soldier who survives the destruction of the base, and also a member of Captain Lennox's team.
Zack Ward as First Sergeant Donnelly, a member of SWAT.
Bernie Mac as Bobby Bolivia, a used cars salesman.

Autobots voices:

Peter Cullen voices Optimus Prime, leader of the Autobots

Chevrolet Camaro in Transformers, portraying the Autobot Bumblebee.Mark Ryan voices Bumblebee

Pontiac Solstice portraying the Autobot JazzDarius McCrary voices Jazz

GMC Topkick, portraying the Autobot Ironhide.Jess Harnell voices Ironhide
Robert Foxworth voices Ratchet

Decepticons Voices:

Hugo Weaving voices Megatron, leader of the Decepticons
Charles Adler voices Starscream
Jess Harnell voices Barricade
Reno Wilson voices Frenzy
Jimmie Wood voices Bonecrusher