CEO Joseph Clayton, 64, said Monday he will retire March 31. He had been CEO since June 2011 and also holds the president title.
Ergen co-founded Dish Network in 1980 and has held executive positions including president and CEO during his tenure.
Satellite provider Dish is facing a changing pay-TV landscape as more viewers stream services like Netflix and Hulu and cable channels like HBO begin to offer standalone streaming services for its own programming.
In an attempt to stay ahead of streaming-service competition, this month Dish introduced $20-a-month online television service Sling TV, which lets users stream channels online without satellite service from Dish or any other subscription.
On Monday, the company said its new subscriber activations edged down 2 per cent to 2.6 million from nearly 2.7 million a year ago. Dish lost about 79,000 net pay-TV subscribers during the year and had about 14 million pay-TV subscribers at the end of 2014.
Dish reported its fourth-quarter financial results as well Monday, a profit of 88 cents per share on revenue of $3.68 billion. Analysts surveyed by FactSet expected a profit of 43 cents per share on revenue of $3.7 billion.
Dish Network Corp. is based in Englewood, Colorado. Before joining Dish, Clayton led Sirius Satellite Radio Inc. for three years, up until November 2004. He also served as chairman of the company from November 2004 through July 2008.