John Hancock Funds, the Boston-based mutual fund business unit of John Hancock Financial, has appointed Andrew Arnott as president and chief executive, succeeding Keith Hartstein, who announced in May that he planned to retire from John Hancock in September after 22 years with the firm. 

Meanwhile, succeeding Arnott as head of John Hancock Investment Management Services is Leo Zerilli, vice president. Zerilli is responsible for all internal and third-party asset manager relationships across the John Hancock and Manulife investment platforms in the US and Asia, as well as guiding the investment product development, product management and market research strategies for IMS. He joined John Hancock in 1997.

Arnott, who has been at the firm for nearly 20 years, most recently served as executive vice president of John Hancock IMS. In that role, he worked closely with Hartstein in overseeing the positioning of John Hancock’s mutual funds product line, and directing the research of economic, investment market and competitive trends.

Prior to heading IMS, he served as chief operating officer of John Hancock Funds, and at various points in his career led product management, development and marketing, the firm said. He also served as director of annuity product development.

John Hancock Funds manages some $74.5 billion in open-end funds, closed-end funds, private accounts, college savings and retirement plans, and related party assets for individual and institutional investors, as at March 31.