A native of Kansas City, Kansas, Allen studied radio, television and film at the University of Kansas. His first professional stint in radio came in 1985 with San Diego’s Smooth Jazz pioneer, KIFM. Two years later Kepler moved from sunny Southern California to Chicago’s WNUA, where he worked on air, in programming, and served as Marketing Director before moving to Princeton to join Broadcast Architecture in the winter of 1990.

By 1990, Kepler had earned a national reputation for his knowledge of Smooth Jazz. In 1992, with the format experiencing challenges in ratings and revenues, Kepler founded BA's now legendary smooth jazz consulting arm, the Smooth Jazz Network™, and began retooling stations including WQCD New York, KTWV Los Angeles, KOAI Dallas, and WNUA. Kepler also served as director of the company's international programming for Tokyo's JOAV-FM (J-Wave). With BA, Kepler has personally consulted over 60 smooth jazz stations and has positioned the company at the forefront of the world of radio research and consulting. "We have forged successful partnerships with client stations in every format in over 100 markets across the United States and more than 25 countries internationally, from Mexico and Canada to the United Kingdom and Japan" Kepler says. "We are seeing tremendous international growth."

“Partnership” is a word that liberally peppers Kepler’s syntax. “We are in fact their partners,” he says. “We don’t just provide our clients with information and leave them on their own to figure it out. We work with them side-by-side to implement successful programming strategies.”

Billboard Magazine writer Ken Tucker described Kepler as "more than a consultant… he’s an evangelist for the smooth jazz format". "While radio consultants are involved in any number of aspects of a radio station's programming, it is downright rare to find them helping a station, let alone a format, sell itself to ad agencies." 

In January of 2007, Kepler took the “Smooth Jazz Network™ to new heights with the launch of the new 24 hour format.  The ‘Superstation’ concept is new for radio. It offers superstar musician talent like jazz legend Ramsey Lewis hosting the daily morning show, world renowned saxophonist Dave Koz on the air every weekday afternoon, and weekend shows hosted by Grammy winning guitarist Norman Brown, brilliant keyboardist Brian Culbertson, international star Paul Hardcastle, and the biggest selling instrumentalist of all time and music icon Kenny G. Some of the most talented radio professionals also host shows on the network like Ramsey’s Chicago co-host Karen Williams, KKSF San Francisco’s midday host Miranda Wilson, format veteran and weekday evening talent Annie Ashe and the Barry White of smooth jazz Billy Raven on the overnight show seven nights a week.

Kepler, who lives in Los Angeles with his wife JoAnn and their four children, is a member of the National Academy of Recording Arts & Sciences. He also serves on the Executive board for the Guitar Center Music Foundation, promoting the importance of music through education and media initiatives and providing financial and in-kind resources to public schools and other non-profit organizations to make music programs available in the communities they serve.