Why was John Glenn Jr so important in American exploratation?

John Glen was the first American to orbit the Earth in a spacecraft. He did so after (1) , Yuri Gargin (a Russian) orbited the Earth, and (2) after Alan Shepard and (3) Gus Grissom, (two Americans) made a suborbital flight. John Glen was the fourth human being to go into space, the second to orbit, and the first American to orbit the Earth in a space capsule.