George competed in both the 5000 metres and the marathon at the 1984 Summer Olympics in Los Angeles. He finished twelfth in heat one of the 5000 metres and so failed to qualify for the next round, and he completed the marathon in 74th place. At the 1988 Summer Olympics in Seoul, he took part in the marathon but did not finish. Mambosasa was the Malawian flag carrier in the opening ceremony at these games.