Clint Hill wanted to be a history teacher. Instead, he ended up participating in some of the most historic and iconic moments of the 20th century.

Hill is best known as the U.S. Secret Service agent who climbed aboard the trunk lid of President John F. Kennedy’s convertible limousine after the president was shot Nov. 22, 1963 in Dallas. It was Hill who pushed first lady Jacqueline Kennedy back into the car and used his body as a shield as the car sped away to Parkland Hospital, where the president was pronounced dead.

Hill told an audience last week at The Carter Center the events of that day were so troubling they eventually resulted in career-ending health problems for the agent.

It was not until 2009, when Hill met journalist Lisa McCubbin, that he opened up about his experiences as a Secret Service agent. Writing his work experiences may have saved his life.

Hill has just released his third book, “Five Presidents,” an account of his service to every president from Eisenhower to Ford.

He was asked at his book event which president he would bring back to serve in 2017. Hill said there were things about each man that he would draw on to make the ultimate president.

Early in his career, Hill was assigned to Eisenhower’s detail. His first trip with the former general was to Georgia, where he often played golf at Augusta National Golf Club.

It was on a subsequent trip to Augusta that Hill was called back to Washington to learn of a new assignment. He would be the lead agent for Mrs. Kennedy.

Hill said his only knowledge of a first lady was Mamie Eisenhower, who never traveled on her own and took her agents to places like teas and fashion shows.

Mrs. Kennedy was more than half the age of Mrs. Eisenhower and was an active traveler and became an international celebrity.

“When she travelled with the president, the crowds would double,” he said.

That was true on that fateful day in Dallas.

Hill punished himself for years with the “what ifs” of that day. He felt if he had been a second or two faster, he could have taken the bullet that ended the president’s life.

A decade later, Hill was there when President Richard Nixon resigned. He was also on duty during the assassinations of Dr. Martin Luther King Jr. and Robert F. Kennedy.

Clearly the most challenging president was Lyndon Johnson, who changed plans without notice to his agents or the military. This was particularly true when Johnson visited his Texas ranch. Johnson might jump in a car to speed down the road to a neighboring ranch or decide he wanted to take a plane or helicopter for an unscheduled trip.

A photo in Hill’s book shows agents and military officers scrambling when they suddenly learned the president was ready to go.

On one trip to Texas, Johnson bought Hill his own set of “ranch clothes,” a casual khaki work shirt and pants the president would wear when there.

“I only wore them once,” Hill said.

Another article of clothing from his Secret Service days suffered a different fate.

When the dying president arrived at the hospital, Mrs. Kennedy didn’t want anyone to see her husband’s shattered skull.

Hill covered the president’s head and shoulders with his suit jacket. The blood soaked jacket was later returned to the agent.

“I had it burned,” Hill said.

Harris Blackwood is a Gainesville resident whose columns appear on the Sunday Life page and on gainesvilletimes.com/harris.