Kirk Lehneis was named president of MainStay Funds at New York Life Investment Management, company spokesman Zach Elvove said.
He replaced Stephen Fisher, who retired this month.
Mr. Lehneis will oversee the suite of mutual funds at MainStay, a subsidiary of New York Life Co. He will continue to report to New York Life Investment Management CEO Yie-Hsin Hung.
Mr. Lehneis is chief operating officer of NYLIM. He will continue to serve as COO in addition to taking on this new role.
MainStay had $80 billion in assets under management as of June 30.