Santiago is the author or co-author of six books and has published articles and book reviews, many of which focus on economic development and the changing socioeconomic status of Latinos in the United States. In 1996 and 2011, Santiago was named one of the 100 most influential Hispanics in the United States by Hispanic Business magazine.[2]
He is a labor economist with expertise in the Caribbean and Central America regions, with a special emphasis on Puerto Rico. He was chair of the Department of Latin American & Caribbean Studies at the University at Albany from 1989 to 1991 and from 1993 to 1995. He is a founding co-editor of Latino Research Review and is a member of the U.S. Congressional Hispanic Caucus International Relations Advisory Group.[5]
Santiago was twice named by Hispanic magazine as one of the United States' "100 most influential Hispanics".[3]
From 2004 to 2010, he was the chancellor of the University of Wisconsin–Milwaukee and held a professorship within its Department of Economics. During his tenure at UW-Milwaukee, he raised 125 million dollars from the private sector for the school's research arm and advocated a 240 million dollar state-funded "UW-Milwaukee Initiative" campaign,[6] before resigning to take the post at the Hispanic College Fund.
Santiago joined the Massachusetts Department of Higher Education in April 2013 as the senior deputy commissioner for academic affairs. In May 2023, Governor Charlie Baker nominated him to serve as commissioner, and the board unanimously confirmed him to serve in the position beginning at the start of July 2015 (after Richard M. Freeland's tenure was scheduled to end).[7] At the start of 2022, Santiago announced his intentions to step down in June 2022.[8]