The 67-year-old Mukasey, accompanied by his wife, Susan, told reporters and cameras at midday Friday that he felt "excellent" as he stepped into a van for a ride back to the Justice Department.
Mukasey never transferred his authority to a deputy during the time when he was rushed to George Washington University Hospital late Thursday and while there under observation during the night. He passed a host of tests Friday, he said, including a treadmill stress test, an MRI and a CT scan.
"As you may have heard, I collapsed briefly last night at the conclusion of a speech," the retired federal judge said in a late-morning e-mail to his departmental staff.
"All tests at the hospital have come back with good results, and I feel fine," Mukasey's e-mail said. "Thank you for your good wishes and your good work. It has been and remains an honor to serve with you."
Mukasey's collapse during an appearance before The Federalist Society evoked memories of similar frightening episodes, including then-Commerce Secretary William Daly's plunge from a stage at the Old Executive Office Building during the Clinton presidency and President George H.W. Bush's emergency trip to a hospital in Tokyo after he took sick at a dinner there.
A Justice spokeswoman, Gina Talamona, had said earlier Friday: "The results are in. Everything looks great." She reported that that Mukasey had passed a treadmill stress test, a stress echocardiogram, CT scan and an MRI. She also said doctors ruled out a stroke or cardiac problem. "He's in good shape," she said.
Talamona also said that physicians specifically had ruled out TIA -- or transient ischemic attack -- which is a mini-stroke.
"There's no indication that he suffered a stroke or any heart-related incident," she said earlier. "It really appears to be a fainting spell."
President Bush telephoned the attorney general shortly before 7 a.m. EST to wish him a speedy recovery, press secretary Dana Perino said, describing Mukasey as "sounding well" and saying he was getting "excellent care."
Talamona noted that Mukasey had had a very busy day before going to a Washington hotel to give the keynote speech to a black-tie dinner of the society, a conservative-oriented legal group. During the talk, he began to slur his words, nodded, turned and started to collapse when he was caught by men standing nearby.
His spokeswoman noted that he "works long days. He's very active. It was a late-night speech under hot lights."
Bush brought the New Yorker in last year to replace Attorney General Alberto Gonzales, who resigned under pressure in a controversy over the firings of several federal prosecutors.
Mukasey opened his speech on terrorism with a wry remark about expecting the mood at the dinner to be "somber or sober." He slumped over the podium about 15 minutes later and could be seen swaying and shaking slightly just before he collapsed and briefly lost consciousness.
"Oh, no, no!" people in the audience cried out as Mukasey fell. "Oh, my God!"
Mukasey is Bush's third attorney general. The flinty but measured lawyer has said the job initially discouraged him, and he has scaled back his public appearances in recent weeks.
A former prosecutor who saw Mukasey hours earlier described the attorney general as tired-looking and drawn.
After collapsing, Mukasey lay on the stage for about 10 minutes being attended to by his FBI security detail and medical personnel at the dinner, said eyewitness Abigail Thernstrom, a senior fellow at the Manhattan Institute. Though he lost consciousness initially, Mukasey appeared to be awake when he was taken from the Marriott Wardman Park Hotel in northwest Washington, she said.
"It was hard to watch such a thing," Thernstrom said. "It was horrible."
A Republican staffer on the Senate Judiciary Committee, Jack Daly, who was also at the dinner, said in an e-mail to colleagues sent at 10:20 p.m. EST: "AG Mukasey collapsed in the middle of his keynote address at tonight's fed-soc dinner. He is still on stage after ten minutes and his security detail has called 911. The paramedics just arrived."
Twenty minutes later, Daly added in another e-mail: "Mukasey did regain consciousness before he was taken away."