In a recent 8-K filing, Sprint revealed long-time chief experience officer Robert “Bob” L. Johnson will be leaving the company at the end of April.

No reason for Johnson’s departure was given in the filing.

“Bob has successfully taken on tremendous challenges throughout his career at Sprint,” Sprint CEO Marcelo Claure said of Johnson. “Under Bob’s leadership we were able to drive substantial improvements and set new performance records in customer care. I thank him for his service and dedication to the company and I wish him well in his future endeavors.”

Sprint announced Wednesday Johnson will be replaced by Robert Hackl as its Chief Experience Officer and President of National Sales. Hackl will report to President and CEO Marcelo Claure when he joins Sprint on April 1, Sprint said.

Hackl comes from his position as commercial operations director at Vodafone in Germany, Sprint said. Before that, Hackl served with T-Mobile in the United States from 2010 to 2013.

Johnson originally joined Nextel in 1998 and came to Sprint when the two companies merged in 2005. During his early tenure at Sprint, Johnson served as Northeast Region president and senior vice president of Consumer Sales, Service and Repair.

In October 2007, Johnson was appointed Chief Service Officer at Sprint.

In 2009, Johnson was named president of Sprint’s CDMA business and took on responsibility for Sprint’s prepaid go-to-market strategy a year later following the departure of the company’s former prepaid president Dan Schulman.

Johnson’s role was again expanded in August 2011 to Chief Service and Information Technology officer, and grew further to President of Retail in October 2013.

Most recently, Johnson was appointed as Chief Experience Officer in November 2014, a role in which he was responsible for customer experience, customer care, Information Technology, shared services and strategic initiatives.