[3] Schnitzer became a partner in the law firm Simpson Thacher & Bartlett LLP early in his career.

[4][5][6] In 2007 Schnitzer joined Travelers as vice chairman and chief legal officer and was on the company's management committees.

[7] In July 2014, he was named chief executive officer of business and international insurance, overseeing areas such as field management, corporate communications, and public policy.

[8][9][10] Schnitzer became chief executive officer of Travelers in December 2015, and was elected chairman of the board in August 2017.

[2][11] Schnitzer is a trustee at the University of Pennsylvania,[12][13] the New York City Ballet,[14] and Memorial Sloan Kettering Cancer Center.