Heinz Kerry, 74, is expected to make a full recovery from the July 7 seizure following additional outpatient treatment, spokesman Glen Johnson said.
"I'm extremely grateful for the quality of care Teresa received," Kerry said in the statement. "I've always known Massachusetts is blessed to have some of the greatest health care in the world, but we've just lived it, and are grateful to all."
Heinz Kerry thanked her doctors and caregivers. "They are the kindest people, who love what they do and do it superbly well," she said.
Kerry praised the State Department Diplomatic Security Service members who first responded when his wife fell ill. Heinz Kerry was treated at a Nantucket hospital and another in Boston before ultimately being discharged from Spaulding Rehabilitation Hospital.
Johnson previously said the cause of the seizure had not been determined but doctors had ruled out a brain tumor, heart attack or stroke. The family does not plan to comment further on Heinz Kerry's health, he said.
Heinz Kerry, an heir to the Heinz ketchup fortune, is the widow of former U.S. Sen. John Heinz, who was killed along with six others in 1991 when a helicopter collided with a plane over a schoolyard in Merion, Pennsylvania. She married Kerry, a longtime senator from Massachusetts, in 1995.
Kerry, the 2004 Democratic presidential nominee, resigned from the U.S. Senate on Feb. 1 after being confirmed to succeed Hillary Rodham Clinton as Secretary of State.