[4] Arkansas-born Hallman began her career at Conoco in 1966[5] where she was hired as a systems analyst directly after graduating from Southern Arkansas University.
[1][5][Notes 1][8][7] Hallman joined Spherion[9] in 2001 as Chief Executive Officer, retiring in 2004.
[12] Hallman replaced Raymond Marcy as Chief Executive Officer in 2001, a role that Marcy had held for over a decade, during which time[Notes 3] Spherion acquired a rival, Norrell Corp. [8] Spherion's prior name was Interim Services.
[15][4] Among the boards of directors on which she served were "Toys "R" Us, Catalyst, United Way of America and Christiana Care Health Systems.
"[16] Beyond having pioneered in what later became known as midsourcing (and receiving various awards),[11][17] Hallman's alma mater wrote about serving as "an inspiration for young women as she met the challenges of corporate leadership and succeeded at the highest levels.