Giacomelli moved into Formula Two in 1977, working in close association with Robin Herd and the March factory. He retired from the Formula Two Pau Grand Prix in May 1977, after his car made contact with one driven by Jacques Laffite. However, he managed to score three F2 wins in 1977 (at Vallelunga, Mugello and Donington Park) and finished fifth in the championship. He also made his Formula One World Championship debut in 1977 in a third works McLaren M23-Cosworth at the 1977 Italian Grand Prix at Monza, retiring with an engine problem which caused him to spin off.