As of 2023 he is the president of the international financial services and investment banking firm Lazard, and is based in its New York headquarters.

[6] He was next one of the original members of the investment bank Wasserstein Perella & Co., and then was managing director in the mergers and acquisitions group at Merrill Lynch.

[8][13][14] During his tenure at Citigroup, McGuire served as business advisor for a number of major deals, including the Time Warner Cable split, ConocoPhillips' acquisition of Burlington Resources, Koch Industries' acquisition of Georgia-Pacific, and the sale of Electronic Data Systems to Hewlett-Packard.

[13] Prior to announcing his candidacy for mayor in late 2020, McGuire was one of the highest-ranking and longest-serving African American business executives on Wall Street.

[15][16] He was a bundler to Barack Obama's 2008 presidential campaign,[17] and was mentioned as a possible candidate for a position in the U.S. Department of the Treasury in 2013.

[22][23] McGuire pledged to focus his campaign on racial unrest amid the George Floyd protests and economic recovery from the COVID-19 pandemic.

[24][25][26][27][28] Three months after beginning his campaign, McGuire had raised $5 million with notable contributions from the business community.