Klinsmann signed a three-year contract with Inter Milan. In spite of the heavily defensive orientated tactics of head coach Giovanni Trapattoni, Klinsmann scored 13 goals in the most competitive league at the time. He was one of the most popular foreign players in Italy, mostly because he had learnt Italian and earned himself the respect of the fans with his appearance and language skills. After finishing third in the Serie A, Klinsmann was called up for the 1990 World Cup in Italy. After qualifying for the round of 16 without any problems, Germany was to play the Netherlands, against which they lost 2 years earlier in the European Championship. It was to be Klinsmann's best international game. After Rudi Völler was sent off in the 22nd minute, Klinsmann was forced to play as a lone striker. He delivered a running and pressure performance with which he occupied the entire Dutch defence, scored the 1–0 opener and was a constant threat. The next day, the German newspaper Süddeutsche Zeitung wrote the following about Klinsmann: "In the last decade, not a single forward of a DFB team has offered such a brilliant, almost perfect performance." After further victories over Czechoslovakia (1–0) and England (1–1 after extra time, 4–3 on penalties), he became world champion after beating Argentina 1–0 in the final. Klinsmann is well remembered for being brutally fouled by the Argentinian Pedro Monzón, who was subsequently sent off, reducing Argentina to ten men.
During the next season, Klinsmann won the UEFA Cup with Inter (2–1 on aggregate against AS Roma) and repeated his previous performance in the league with 14 goals. Klinsmann's contract was extended until 1994. But a disastrous 1991–92 season made all plans fall through. Inter Milan never managed to gain any momentum under coach Corrado Orrico and finished eighth in the league, with Klinsmann only scoring seven goals and the team being divided and fragmented into groups. It was clear for Klinsmann that this would be his last season at Inter Milan. Because of the poor season at Inter Milan Klinsmann temporarily lost his position in the starting 11 in the German National Team to Karl-Heinz Riedle. Only due to an arm fracture of Rudi Völler did Klinsmann regain his starting place for Germany in the opening game of Euro 1992 against the CIS. His performances improved from game to game during the European Championship and he was one of the best in Sweden. Here it comes his best goals under Inter of Milan shirt :