UnitedHealth tapped its president, David Wichmann, to replace Stephen Hemsley as CEO, effective Sept. 1.
Hemsley, 65, will remain with the company in the newly created position of executive chairman.
Richard Burke, its current board chairman, will become a lead independent director.
Wichman, 54, has a long history with UnitedHealth Group, having joined the company in 1998. He was chief financial officer from 2011 until mid-2016, when he was named president of UnitedHealth Group. Wichmann also has overseen UnitedHealthcare, the company's benefits business, since 2014.
"This is the right time for this transition to take place, as the company is performing strongly and has a positive outlook for the foreseeable future, and Dave Wichmann is the right choice to succeed as CEO for that future," Hemsley said in a statement.
UnitedHealth shares are up more than 37 percent over the past year.