Who was the first American to reach space?

U.S. Navy test pilot Alan Shepard joined the astronaut program in 1959. He became the first American and the second man in space on May 5, 1961, when he piloted the Mercury spacecraft Freedom 7 on a 490-kilometer (300-mile), 15-minute suborbital flight. He would return to space nearly a decade later as an Apollo astronaut.

Source: National Air and Space Museum