Post peaked in 1955-56, when he hit 40 and 36 HR respectively for the power-hitting Reds. His numerous tape-measure homers led many to consider him the most powerful slugger in the NL during this period. Following the 1957 season, he was traded to the Phillies for Harvey Haddix, but Post returned to Cincinnati during the 1960 season. His career-high .585 slugging percentage in part-time duty helped the 1961 Reds to the NL pennant. In the World Series, his two-run homer in Game Five went for naught as the Yankees clinched with a 13-5 win.
Post broke into baseball as a pitcher in 1946 and went 17-7 in 1947 for Muncie (Ohio State League), but he was soon switched to the outfield to take advantage of his heavy hitting. He had brief stints with the Reds before finally sticking in 1954. Besides his 40 HR in 1955, he had other career highs with 109 RBI, 116 runs, 33 doubles, and a .309 average, but led the league in strikeouts for the first of three times. Much-used as a pinch hitter from 1958 on, his best effort in that role came in 1962 (9-for-27).