He will succeed Stuart Reese, who will take the role of nonexecutive chairman of the board, the Springfield company said Monday.
Crandall, 44, has been MassMutual's president and chief operating officer since December. He will remain president when he assumes the chief executive position in January.
Crandall has worked at MassMutual since 1988. He has held several leadership positions in the firm, including head of corporate bond management, public bond trading and institutional fixed income. He was MassMutual's chief investment officer and chairman of its Babson Capital Management LLC unit from June 2005 to November 2008.
He was named president and chief executive of Babson in March 2006.
Reese, who has worked for MassMutual since 1993, has been chief executive since 2005.
