In the 1940s he won numerous smaller tournaments in Latin America and in 1946, the American Indoor Championships. However, in the U.S. Championships at Forest Hills, he came across the semifinals addition, never.
In 1947, Segura joined the tennis pros and played as against Jack Kramer and Pancho Gonzales, the strongest tennis players of that time. Although he was always in the shadow of that player, but he could win the American professional championships from 1950 to 1952 three times in a row.
Segura was a young tennis player with bow legs, but he could be offset these disadvantages by its excellent footwork and his doppelhändige forehand. Jack Kramer, another well-known tennis players in the forties and fifties, said of this blow, he was the best blow that ever was in tennis.
After his resignation as a tennis player Segura worked as a tennis coach and coached among others the young Jimmy Connors.
In 1985, he was inducted into the Hall of Fame of tennis.