His hiring comes a day after the Pirates added former World Series MVP David Eckstein in a similar role.
The Rangers fired Banister as manager in September. He was 325-313 as the team's manager and led the Rangers to back-to-back American League West division titles in 2013-14.
Before joining the Rangers, the 54-year-old Banister was with the Pirates organization for 29 seasons, including serving as bench coach from 2010 to 2014.
"Jeff Banister returns to the Pirates as a valuable resource, instructor and advisor for our front office, Major League team and player development system," general manager Neal Huntington said in a statement. "Jeff brings a wealth of knowledge, experience and a passion for the Pirates back to the organization. We are thrilled to add a quality person and baseball man to help an organization that he loves get better."
Eckstein, 43, won the World Series MVP award in 2006 when he helped the St. Louis Cardinals defeat the Detroit Tigers when he hit .364 in five games. He played 10 seasons in the majors and also won a World Series title with the Los Angeles Angels.
Eckstein's younger brother, Rick, was named the Pirates' new hitting coach earlier this offseason.