Sprague, 48, joined Kia in August 2008 from Ford Motor Co., where he led marketing for the Lincoln and Mercury brands.
In his new role, he will oversee all U.S. sales and marketing activities for Kia. As part of the restructuring, Kia said its U.S. retail development efforts will also report to him.
In the statement, Kia credited Sprague for the launch of 16 all-new or revamped models while also raising "consumer awareness, perception and consideration for the brand through expanded marketing activities."
Under Sprague, Kia's profile has been broadened through Super Bowl advertising and a well regarded marketing campaign for the boxy Soul subcompact, featuring hamsters.
Kia also renewed and expanded a high-profile sports marketing deal in October 2010 with the National Basketball Association, and signed on as a sponsor for the LPGA, under Sprague. The NBA and Kia first signed a marketing pact in January 2008.
Loveless joined Kia in 2007 as vice president of sales after a 24-year career at Chrysler Group.
At Kia, he led the company's sales operation through a period of rapid growth in which it set annual U.S. sales records in 2010, 2011 and 2012. The company's U.S. market share grew from 1.9 percent when he joined in 2007 to a high of 3.8 percent in 2012 before receding to 3.4 percent last year.
Also during Loveless' tenure, Kia posted 27 consecutive monthly U.S. sales records through Nov. 2012.
Loveless' exit is the second recent departure of a high-ranking U.S. executive from a Korean automaker.
In December, Hyundai Motor Co. replaced John Krafcik as CEO of Hyundai Motor America with Dave Zuchowski, formerly head of U.S. sales. Hyundai said at the time Krafcik was employed under a contract that ran through the end of 2013.
It's unclear whether Loveless was forced out or resigned.
But Kia and its parent, Hyundai Motor Group, have a history of keeping U.S. executives under tight reins, sometimes parting ways if they don't reach sales targets.
Separately, Kia promoted Adam Perlow to vice president of sales operations from serving as eastern region executive director. Perlow will report to Sprague.