[4] Marson made his first Paralympic appearance, representing Italy, in the second ever Games in Tokyo, Japan, in 1964.

In the individual fencing events Marson won silver in épée and sabre, but alongside compatriots Franco Rossi and Renzo Rogo he won a team épée gold medal and a team sabre bronze medal.

He was joined by Giovanni Ferraris, Vittorio Loi, Franco Rossi and Germano Zanarotto to defeat France 5–4 in the final and win gold for Italy in the team foil.

[1] He successfully defended the Paralympic javelin and discus titles that he had won in Tokyo and added a third athletics gold medal in the club throw and a bronze in the shot put.

He finished fourth in the men's discus 4 event with the gold being won by Canadian Eugene Reimer.