[14] He received a BA in economics from Boston College,[15][16] where he played collegiate soccer,[17] in 1989,[18] and an MBA in finance from New York University's Leonard N. Stern School of Business.

[1] He held a number of senior executives roles at a portfolio company of GE Capital, which specialized in alternative risk insurance and reinsurance.

[3][24][27] He streamlined the company's operations and staff, improved profitability,[1] made acquisitions, and hired high-profile executives.

[33][25][26] In April 2011[34] MMC appointed him president and CEO of its subsidiary Marsh, Inc.,[3] a global insurance brokerage[34] and risk management firm.

[35] Under Zaffino, Marsh grew in part via acquisitions, and the company launched several technological products[36] such as a mobile platform.

[41] Zaffino was appointed executive vice president and global chief operating officer of AIG effective August 2017.

[45][29][33] In September 2017,[7][46] Duperreault appointed Zaffino as CEO of General Insurance,[7] in addition to his position as global COO.

He also continued to lead the firm's General Insurance unit as CEO until August 2020, when that position transitioned to David McElroy, as Zaffino moved to focus more on enterprise-wide leadership responsibilities in his role as president and global COO.

[10] Zaffino is credited with significant roles in restructuring at AIG[49][50] and with the turnaround in its underwriting to restore the insurer to profitability,[51][52] as well as with steering the company through historic insured losses from natural disasters,[53] including Hurricane Ian’s $450 million cost to AIG,[54] and unique challenges resulting from the invasion of Ukraine.

[56][57] He was appointed to the board of the New York Police and Fire Widows' and Children's Benefit Fund in 2013[27] and in 2015 was the honoree at its annual gala.