(CNN) -- Jefferson Thomas, one of the so-called "Little Rock Nine," the nine students who integrated Central High School in Little Rock, Arkansas, in 1957, has died, according to Carlotta Walls LaNier, president of the group's foundation. He was 67. Thomas died of pancreatic cancer on Sunday, the Little Rock Nine Foundation said in a statement. He was living in Columbus, Ohio. As a 15-year-old, Thomas was one of the nine African-American students who braved segregationist mobs to integrate the all-white school under the protection of military forces. A retired federal accountant for the Department of Defense, Thomas "had spent the last decade of his life doing community service, traveling to promote racial harmony and supporting young people in seeking higher education," the foundation said. In 1999, he and the others received a Congressional Gold Medal from President Bill Clinton.
@highlight
NEW: President Obama praises Thomas' bravery
@highlight
Thomas died of pancreatic cancer on Sunday
@highlight
He was 15 when he and others integrated Arkansas schools in 1957
@highlight
Other Little Rock Nine members remember Thomas as being able to keep them laughing
"I will miss his calculated sense of humor," said @placeholder, another member of the nine.
"We stay in contact because we had that experience, and we grew up together in @placeholder," she said.