While Clemente had begun to fulfill his potential, the Pirates continued to struggle through the 1950s, although they did manage their first winning season since
1948 in 1959. During the winter season of 1958-59 Clemente didn't play winter baseball in Puerto Rico; instead, he served in the
United States Marine Corps Reserves. He spent six months in his military commitment at
Parris Island, South Carolina, and
Camp LeJeune in
North Carolina. In Camp Lejeune he served as an
infantryman. The rigorous training program helped Clemente physically. He added strength by gaining 10 pounds and said his back troubles had disappeared. He would remain in the reserves until September of 1964. In
1960, the team compiled a 95-59 record, a National League pennant, and seven-game
World Series victory over the
New York Yankees. Clemente batted .310 in the series, hitting safely at least once in every game. His .314 batting average, 16 home runs, and defense earned him his first trip to the
All-Star game. Through the rest of the decade, Clemente firmly established himself as one of the premier players in baseball. For the rest of his career, he batted over .300 in every year save
1968, when he hit .291. He was selected to every All-Star game; and he was given a
Gold Glove after every season from
1961 onwards. He led the National League in batting average four times (1961,
1964, 1965, and
1967), led the National League in hits twice (1964 and 1967), and won the Most Valuable Player award for his 1966 season, when he hit .317 while setting career highs in home runs (29) and RBI (119). In 1967 he registered a career high .357 average and scored twenty-three home runs and 110 runs batted in.