Mataczynski is leaving the developer to "pursue other opportunities in his professional career and a new chapter in his family life", according to the company. He has led RES Americas since 2005.
Chairman Vic Fryling, who was chief executive from 2003 to 2005, will act as interim CEO.
Wind energy projects Mataczynski has overseen during his time at the helm include the development of a 1.25GW wind farm planned with Puget Sound Energy (PSE) and the sale of the 140.4 MW Marengo wind project to MidAmerican Energy Holdings in 2006. Both projects are in Washington state.
Ian Mays, CEO of parent company RES Group, said: "RES Americas has grown significantly in the five years that Craig has been its chief executive.
"I would like to thank him for the hard work and leadership that he has provided in helping create the considerable success RES Americas is today, and also for his valuable contribution to the broader group."
In the last five years, RES Americas has developed 985.4 MW of wind power in the US, either on its own or jointly with other developers.