Several foreign-born athletes have represented the United States at the opening ceremonies. Irishman Pat McDonald was the first in 1920.

McDonald competed for the United States in the 1912 Summer Olympics where he won the gold medal in the shor put.held in Stockholm, Sweden in the shot put where he won the gold medal. McDonald also finished second behind teammate Ralph Rose in the shot (two hands) competition, where the distance thrown with each hand was added together.

McDonald returned 8 years later after World War I to compete in the 1920 Summer Olympics in Antwerp, Belgium. Here he won the Gold medal in the 56 lb weight throw in the second and final time this competition was held in the Olympic program.

Rolf Monsen, a multi-discipline Winter sports athlete born in Oslo, Norway, competed as an American in 1928 and 1932. He qualified for the 1936 Games and though an injury prevented him from taking part, he was still chosen to carry the flag.

The American team at the 1936 Summer Games were led by Berlin-born, highly regarded gymnast Al Jochim.

Olga Fikotová was a discus-thrower at the 1956 Summer Olympics and the only athlete to win a gold medal for her home country Czechoslovakia in that year. After moving the U.S., she would go on to compete for her adopted country in the next four Summer Games. Despite not being able to replicate her success, Fikotová was chosen to lead the American team at the 1972 Games in Munich, West Germany.

More Info: en.wikipedia.org