"I have worked closely with Jim throughout my career at Host and I believe that he is the ideal individual to drive the future success of the company," Walter said in a statement.
It is unclear why Walter is leaving, and Host Hotels did not immediately respond to a request for comment. He served as CEO of the Bethesda, Md.-based lodging real estate investment trust since 2007.
Risoleo, as executive VP, is also managing director of Investments, West Coast and Europe. He will gain a seat on the company's board of directors. Risoleo joined the company in 1996 and has overseen investments in Europe since the company began business there in 2006.
Walter will remain with the company until Jan. 31 to "ensure a seamless transition of leadership responsibilities," according to Host Hotels.
Shares of Host Hotels were up 1.24% to $19.11 in early mid-morning trading.