Michael, 35, worked with Whisenhunt on the Chargers' offense during the 2013 season.
"Jason really impresses me with his knowledge of the run and pass game and he was a big part of putting together our plans last year in San Diego," Whisenhunt explained in a statement issued by the Titans. "He is very familiar with the offensive system that we want to implement here, which includes bits and pieces from a number of offensive systems.
"He is intelligent and a good communicator," Whisenhunt added. "He was responsible for presenting a couple of game-plan packages to our offense each week and he was impressive."
Michael has collected eight years of NFL coaching experience with the Oakland Raiders, New York Jets, San Francisco 49ers and Chargers after leading Western Kentucky to the 2002 NCAA I-AA (now FCS) championship as a star quarterback.
Although Michael will direct daily meetings and oversee the offense, this is still Whisenhunt's scheme. The latter will retain play-calling duties.
Whisenhunt has yet to hire a defensive coordinator. NFL Media Insider Ian Rapoport has reported that Pittsburgh Steelers linebackers coach Keith Butler is the top choice, with former Cleveland Browns defensive coordinator Ray Horton as the fallback option.