McCain has shown he is "reaching across the aisle in order to get things done," Schwarzenegger said during a news conference. The GOP presidential hopeful has "crusaded to end wasteful spending in Washington" and has a "great vision" to simultaneously protect the environment while stimulating the economy.

Schwarzenegger's endorsement is the second major backing in less than 24 hours for McCain. On Wednesday, McCain garnered the endorsement of former New York Mayor Rudy Giuliani, who dropped his bid to be the GOP standard-bearer in November. Giuliani shared the podium Thursday with McCain and the California governor.

McCain said he was honored to pick up Schwarzenegger's endorsement and his remarks about protecting the environment while growing the economy through so-called green-clean technologies.

He pledged to work to "hand our children a cleaner planet than the one we have today."