Deal, in a Friday interview with The Associated Press, said the legislation "sends a signal that the citizens of our state believe the rule of law is important."
The bill passed late Thursday, mere hours before the end of Georgia's 2011 legislative session.
When a congressman, Deal backed tough measures aimed at illegal immigration.
On Friday, Deal said he did not think Georgia law would lead to boycotts or harm businesses in the state. He did say he hopes it will "send a message to members of Congress that it's time for them to get serious about the issue."