In 1958, Andersson completed his compulsory military service with the United Nations (UN) peace-keeping force in the Gaza Strip. During this service he survived typhoid and a fire. Upon returning home he attempted to rejoin the UN but with little success. A friend encouraged him to join him in a rally, in which the pairing finished in 6th place. Local rally drivers saw that he had potential, but as he had little money he could not afford to race. His friend Bengt Söderström became a Saab factory rally driver, and Andersson was able to borrow parts to make his car more competitive. The UN eventually offered him the opportunity to serve in the Congo, but he turned it down to concentrate on his rallying career.