Gradín played in the first South American Championship held in Argentina, where Uruguay became the first champions of the tournament, and finished as top scorer.

[3] Gradín arrived at Peñarol in 1915 where he immediately made an impression, gaining selection for the national team in his first year.

[7] Gradín's racial background became an issue with Chile complaining before and after their match with Uruguay that the Uruguayans were unfairly selecting "Africans".

[11] The 1919 South American Championship had Gradín playing all of Uruguay's tournament matches and scored two goals.

[12] Gradín playing on a foreign national team in Brazil did not quell the support he received from black Brazilians.

[14] This led to him missing out on selection during Uruguay's successful tournament run when they won several South American Championships and an Olympic gold medal.

[3] Gradín's playing style inspired Peruvian poet Juan Parra del Riego to compose a poem Polirritmo al jugador de fútbol in his honour.

[1][9][17] In 1922 at the unofficial South American Championships known as the Campeonato Latino-Americano, Gradín won a gold medal in the 400 metres sprint.

On 17 December 1944, the day they had won the Uruguayan championship, the entire Peñarol team visited him at the Pasteur Hospital, dedicating their win to him.

[3] A biography of his life was released in 2000 by Uruguayan author Carina Blixen entitled Isabelino Gradín : testimonio de una vida.