[citation needed] He then began a doctorate in art history under Christopher Gray with a thesis on the early years of Jackson Pollock, which he completed in 1965.
[8] O’Connor remained a member of the Pollock-Krasner’s "authentication board," devoted to distinguishing real Pollocks from forgeries, and frequently testified on behalf of the foundation during litigation.
[9] One article about such a dispute described O’Connor as a "stately Old World-style connoisseur with a Vandyke beard and curled mustache, who believes erudition and a practiced eye are essential to judging authenticity.
"[10] In the 1980s, O'Connor worked intensively on the history of American murals and received a grant from the United States Capitol Historical Society for his research.
[11] In 2010 he created a website called The Mural in America to publish decades of work on the vast subject of wall art in the U.S.[4] He died suddenly, at his home in Manhattan, in 2017.