Former U.S. senator and astronaut John Glenn speaks during an interview at the Ohio Statehouse in Columbus, Ohio, in 2015. (Paul Vernon / Associated Press)

John Glenn, who became an American hero as the first U.S. citizen to orbit the Earth and then relived that glory 36 years later as the oldest man to go into space, has died. He was 95.

Glenn, who also served for 24 years as a U.S. senator from Ohio, died after being hospitalized in Ohio on Wednesday.

Ohio State University President Michael V. Drake confirmed his death, releasing a statement Thursday.

“The Ohio State University community deeply mourns the loss of John Glenn, Ohio’s consummate public servant and a true American hero. He leaves an undiminished legacy as one of the great people of our time,” he wrote.

In his first historic flight, Glenn circled the Earth for nearly five hours in a tiny spaceship on Feb. 20, 1962. To return to space on a nine-day mission aboard the shuttle Discovery in 1998, he had sold himself as a human guinea pig who — at 77 — would demonstrate the effects of space travel on the elderly.

The second celebrated trip did nearly as much to revive interest in America’s space program as his first pioneering voyage had to ignite the country’s fascination in space exploration.

Glenn first earned broad public attention in 1962 in the bell-shaped space capsule Friendship 7 — a flight that NASA’s mission control worried might burn up upon re-entering the Earth’s atmosphere. Epitomizing the fighter-jock pilot of few words mythologized in Tom Wolfe’s “The Right Stuff”, Glenn exited the capsule smiling and jauntily walked across the awaiting aircraft carrier deck as if he had just returned from a cross-town errand.

Glenn was the last surviving astronaut of the original Mercury 7 group. The others were Alan B. Shepard Jr., Gus Grissom, Wally Schirra, Gordon Cooper, Deke Slayton and Scott Carpenter.

A war hero and test pilot who earned fame even before he was named to the Mercury team, Glenn seemed to have the right stuff and more.

Not only did Glenn “have courage and ambition, but he also had supreme confidence in himself and his own abilities,” qualities that distinguished him from most mortals, said Frank Van Riper, who wrote the 1983 biography “Glenn: The Astronaut Who Would be President.”

“That type of confidence can let him sit atop a rocket and have his blood pressure not change at all.”

After his first space flight, Glenn, then 40, was elevated to celebrity status as much by his personal charm and heroics as he was by the pioneering era that he helped define. Before Glenn made his three loops around Earth in a four-hour, 56-minute flight, only Soviet astronauts, test dummies and dogs had made historic “firsts” in space. Almost a year before Glenn defied gravity, cosmonaut Yuri Gagarin had become the first man in space.

Glenn was neither the first or second American in space. Those distinctions belonged to Shepard, whose entire voyage lasted 15 minutes and who was followed months later by Grissom. Yet Glenn’s flight raised the most passion and publicity in America. Glenn stayed aloft for hours, focusing Americans’ rapt attention on his every orbit and ultimately restoring America’s confidence in its technological prowess.

President Kennedy was apparently so relieved that Glenn helped put America back in the space race, and so concerned about the astronaut’s well-being, that he vetoed a return to space by Glenn. Rather, Kennedy marked Glenn as an American with a political future. After a few early political defeats, the astronaut was elected to the U.S. Senate from Ohio in 1974.

Although Glenn remained a supporter of NASA, he tried to steer clear of being seen as the Senate “astronaut,” preferring to make his mark in other areas. He was perhaps best known as the author of bills to restrict the proliferation of nuclear weapons around the world. He also helped pass legislation to clean up radioactive waste at the nation’s nuclear weapons sites.

Yet his drive to return to space never fully abated, and he relentlessly lobbied the National Aeronautics and Space Administration for another space flight. Glenn insisted that he was not driven to return to space for the thrill of the ride or as a passenger with a congressional free pass but as a scientist-explorer.

“What you’re up there for,” he said, “is to accomplish something for the country that may break us into some new areas of research that may benefit an awful lot of people.”

After his late-in-life flight, dozens of tests done on his body showed that he handled the rigors of space as well as astronauts roughly half his age, NASA scientists said when results were released in 2000.

In 2012, Glenn and Carpenter received a hero’s welcome when they returned to the Cape Canaveral launchpad to mark the 50th anniversary of Glenn’s orbital flight.

The national attention after the 1962 flight was “almost unbelievable,” Glenn said at the event, and added that he and his colleagues learned to live with the acclaim “or tried to anyway.”

John Herschel Glenn Jr. was born July 18, 1921, in Cambridge, Ohio. His mother, Clara, a teacher, and father, John, soon moved to the tiny town of New Concord, where his father opened a plumbing business. At 3, he met Anna “Annie” Castor, the 4-year-old daughter of the town dentist. The pair started dating in high school and married in 1944.

In high school, Glenn was an honors student who excelled in sports and student politics — and played the lead in the senior class play.

A religious young man, Glenn enrolled in Muskingum College, a small Presbyterian school in New Concord, where he sang in the church choir and played football. While there, Glenn learned to fly through a civilian program run by the Navy.

When it came time to enlist, he joined the Marines, leaving college behind after Japan attacked Pearl Harbor.

During World War II, he rose to the rank of captain and decided to make a career in the military. By the end of the war, he had flown 59 missions with F-4U fighters, and was awarded two Distinguished Flying Crosses and 10 Air Medals.

The Korean War meant 90 more missions for the Marine aviator, and many more medals, including a third and fourth Distinguished Flying Cross.

“Glenn grew up with the archetypal Protestant work ethic and the idea that good things happen to people who work hard,” Van Riper said. “Add to this sense of confidence and the idea in the military that you succeed if you work hard, and it explains why he pursued tougher and tougher assignments.”