Only twice has a hitter hit above .400 for a season. But this turns out to be a slightly more interesting topic than it might seem, at least to me. The big twist here is that both of these seasons were well over .400 - in fact both were over .420! Nobody ever hit between .400-.420, but two guys hit over that.
Max Carey: .429 (1922)
Max Carey’s 1922 season still holds the record for batting average, hits, and singles in a season. He had 247 hits that year, out of which 195 were singles. That still left room for 31 doubles, 18 triples, and 3 HR, and he added 59 walks. He slashed .429/.482/.561. In his Hall of Fame career, Carey had more than 3000 hits, over 550 SB, scored more than 1400 runs and drove in more than 1100. He played for the Phillies for two years, then was traded to the White Sox, but sadly I don’t know who the Phillies got. Surely it wasn’t enough.
Paul Waner: .421 (1934)
Paul Waner was a better hitter than Carey, though without the steals, and playing RF instead of CF. And unlike Carey’s year in 1922, Waner’s 1934 season was deemed worthy of the MVP, the first of three straight MVPs for Waner. Interestingly, both players were in their thirties when they hit .400 - Carey was 32, Waner was 31. Waner had 34 doubles and 21 home runs that year. He added 96 walks, and had an overall OPS of 1.142, which probably relates to the MVP.
Waner was later inducted into the HOF. Like Carey he started his career with the Phillies, but was traded to the Yankees before his MVP seasons. Maybe Philadelphia's GM wasn’t making such great decisions?