Kelly, an astronaut scheduled to command the next space shuttle mission in April, shared the good news with reporters at NASA's Johnson Space Center in Houston today, a short drive from the rehab center where Giffords is being treated for her brain injury.
Kelly shared details of Giffords' progress. He said the congresswoman receives daily briefings from her staff.
"She is improving every day, and in the realm of brain injuries, that is very significant and pretty rare," Kelly said.
Watch "World News with Diane Sawyer" for the latest on Giffords' condition tonight on ABC.
The astronaut also said his wife is also beginning to learn about the horrific shooting in Tucson on Jan. 8 that nearly took her life and killed six people, including a member of her congressional staff. Besides Giffords, a dozen others were injured in the attack, which happened while Giffords was meeting with constituents outside of a Safeway grocery store.
While Giffords apparently did not remember the attack, Kelly said that she is now beginning to cope with the tragedy.
"Despite that, she remains in a very good mood," he said.
The mission commander spoke to the press with members of his crew, who are set to fly space shuttle Endeavor's final mission next month. Pending "final approval" from her doctors, Giffords plans to watch the launch at the Kennedy Space Center in Florida, Kelly said, adding that there's a "pretty good chance" it will happen.
Kelly visits his wife every morning at TIRR Memorial-Hermann rehab hospital before heading to NASA for training, and he returns to the hospital every evening when he's done. At the press conference today, every member of the STS-134 crew was wearing a blue bracelet in honor of Giffords.
In an interview with ABC's Diane Sawyer in January, Kelly shared his hope that his wife would make a "100 percent recovery" and that even from her hospital bed, she was already showing signs of improvement.
"She spent 10 minutes rubbing my neck and I keep telling her, 'Gabby, you're in the ICU. You know, you don't need to be doing this,'" Kelly said with a chuckle.
Other hopeful signs have emerged in the weeks since, with Giffords standing for the first time and then speaking. In February, her doctors announced that Giffords had recovered to the point where she was able to ask for toast for breakfast.
On the one-month anniversary of the attack, Kelly wrote a Facebook post thanking the public for support and saying that Giffords was recovering at "lightening speed." But still, Kelly and his wife's family say they know her recovery will take time.
"Gabby's got a long road ahead of her," Kelly told Sawyer in January. "The recovery from these kinds of injuries isn't measured in days and weeks. It's more like weeks and months. ... But you know, she's a really, really tough woman."
The Associated Press contributed to this report.