Born in Aghia Sophia in Piraeus, Yfantis joined the senior side of Olympiacos F.C. at the age of 17. He played for the first time in an official match in 1953. He played as a forward and scored 225 career goals in all competitions. In A'Ethniki, he not only played in 58 games in three seasons and scored 30 goals, but he had also scored first for the historic struggle of Olympiacos in European competition against AC Milan (final score 2-2). Serious injuries forced him to quit football in 1964 at the age of 28.