Disambiguation: Steve Rogers, Earth-616
First published in: 1941
Captain America first appeared in Captain America Comics (Marvel, 1941 series) #1 (March 1941). His first appearance in the Marvel Universe was in The Avengers (Marvel, 1963 series) #4 (March 1964), where it was revealed he had been frozen in ice since 1945. He became Nomad from Captain America (Marvel, 1968 series) #180 (December 1974) to #183 (March 1975). He first used the codename "The Captain" in Captain America (Marvel, 1968 series) #336 (December 1987), but didn't wear The Captain's uniform until issue #337 (January 1988).
Link: https://en.wikipedia.org/wiki/Captain_America