"President Reagan believed deeply in American character and destiny. He believed deeply in the power of freedom to improve the lives of average men and women," Mr. Bush said at a Capitol ceremony.
"These ideas changed America and they changed the world, not only because he eloquently explained them, because they were right."
The former president, who is 91 and has Alzheimer's disease, did not attend.
Mrs. Reagan said the ceremony was an emotional experience for her. The event took place, she said, in very place where she and her husband stood after his 1981 inaugural and learned that the American hostages in Iran were free and on their way home.
"This is, very obviously, a very special occasion for me, and very memorable," she said. "I want to thank you, all of you, for all your expressions and what you've said."
President Clinton signed the Gold Medal resolution for the Reagans in July 2000. It praised Reagan, who served 1981-1989, for his leadership in restoring optimism to the nation and bringing an end to the Cold War. Mrs. Reagan was recognized for her efforts to curb alcohol and drug abuse among the nation's youth.
According to the White House, it is up to congressional leaders to decide when to present the award to an honoree.
"Ronald Reagan is one of the largest figures of our time. His name will always stand for courage and consistency, for patriotism and resolve, and for humor and optimism," Mr. Bush said. "He's a man of great talent and great character. His entire career is a tribute to the power of great ideas."
George Washington received the first Congressional Gold Medal in 1776. The only presidential couple to receive it was Gerald and Betty Ford in 1998.
Mr. Bush previously gave the medal to the family of the late Cardinal John O'Connor of New York and to 29 Navajo Indians for creating an unbreakable code used by the Marines during World War II's fiercest battles.