[2] He retired as chief executive officer (CEO) in December 2012.

[3] McCallister earned his bachelor's degree from Louisiana Tech University in 1974,[4] and joined Humana in 1974 as a finance specialist.

In 1996, he was the division president of the firm's Texas, Florida, and Puerto Rico operations, before becoming CEO of Humana in February 2000.

[6] With a total compensation of $14.13 million in 2010, McCallister ranked 66th on the Forbes executive pay list.

[4] McCallister is on the boards of directors of AT&T Inc.,[7] a role he has been in since February 2013, and Syracuse University's Institute for Veterans and Military Families.