Atlanta general manager Frank Wren made the announcement Friday.
Walker, the Braves' third hitting coach in three seasons, worked in the same capacity since 2003 with the Chicago White Sox. First baseman Paul Konerko routinely praised Walker for helping him revive his career as a slugger.
But Walker didn't fare well this year with high-priced designated hitter Adam Dunn, who posted career lows.
Parrish's one season ended with the Braves falling from first in NL on-base percentage in 2010 to 14th. Hitting woes contributed to Atlanta blowing an 8½-game wild card lead in September.
Right fielder Jason Heyward, whose numbers dropped off dramatically last season, will be one of Walker's early projects.