The ceremony also honored Tyrone Woods and Glen Doherty, Navy SEALs who have been identified as CIA contractors.
"Ty Woods and Glen Doherty died defending the U.S. annex in Benghazi," Kerry said. "And thanks to their bravery and their sacrifice, 30 Americans escaped the attack. Thirty Americans are alive today because of Ty and Glen.
"Ty Woods was a guy who was always looking for a challenge, always waiting for the phone to ring and for the next big mission," Kerry said.
"Even though he got a scholarship to wrestle for the University of Oregon, Ty joined the SEALs at 18 because he thought it was the biggest challenge that he could set for himself. He earned a Bronze Star and a Combat V, but he also had a healer's touch, and he eventually became a registered nurse and a certified paramedic."
Shortly after Woods died, then-Secretary of State Hillary Rodham Clinton said he had "the hands of a healer as well as the arm of a warrior."
Kerry said: "Glen Doherty protected our diplomatic posts around the globe from Iraq to Afghanistan, and finally, to Libya.
According to his SEAL buddies, Glen was, without a doubt, the most-liked man you could ever hope to meet. Whether he was skiing or surfing, running or rafting, Glen always wanted to be doing something and always wanted to be connecting with other people."
His family and friends established the Glen Doherty Memorial Foundation in his honor.
Ragaei Abdelfattah, formerly a Prince George's County, Md., master planner, was working for the U.S. Agency for International Development when he was killed during an August suicide attack in Afghanistan.
"He was Egyptian by birth," Kerry said, "but his friends and family called him the biggest flag-waving American they ever knew. He loved bad chain restaurants, bad romantic comedies and dark chocolate."
The ceremony also belatedly honored two Foreign Service officers killed in Vietnam: Joseph Gregory Fandino in 1972 and Francis J. Savage in 1967.
Each of those honored "sought out the most difficult assignments," Kerry said. "They understood the risks, and still they raised their hands and they said: 'Send me.' "
Davidson writes the Federal Diary column for The Washington Post.