Long considered one of the world's preeminent experts on wildlife, Knoxville, TN, native Jack Hanna evinced fascination with animals from an early age; he began his occupational life as assistant to a Tennessee veterinarian, then worked as the co-proprietor of a Knoxville pet shop with his wife, Suzi. A lengthy series of zoo-related posts followed, including a two-year tenure at the Central Florida Zoo and a 14-year tenure at the Columbus Zoo; during that time, Hanna also commenced appearances with animal friends on talk shows including The Late Show with David Letterman, Good Morning America, and Larry King Live. By 1992, Hanna's show-business activities grew so overwhelming and taxing that they forced him to withdraw from his Columbus post, but he nevertheless retained the title of zoo director emeritus in Columbus over the following decades. Hanna branched out into emceeing his own television series beginning in the 1990s, with two programs designed to provide information about exotic wildlife to the general public: ZooLife with Jack Hanna (1993) and the Emmy-nominated Jack Hanna's Into the Wild (2007). Meanwhile, he also continued his frequent talk-show appearances.