After obtaining his MBA he then joined the management consultancyBooz, Allen & Hamilton in New York. He left in 1989, to obtain his PhD degree and afterwards started working at Johns Hopkins University in Baltimore, where he served as history of art professor and department head from 1992 to 2001 and as dean of faculty from 2001 to 2002. In 2002, Weiss started serving as dean at Johns Hopkins University's Krieger School of Arts and Sciences. From 2005 to 2013, he then served as president of Lafayette College. In 2016, the college named their new black box theater in William C. Buck Hall for Weiss and his wife, Sandra. From 2013 to 2015, he served as the president of Haverford College.
Metropolitan Museum
Weiss was appointed the president of the Metropolitan Museum of Art in 2015. In 2017, he was named as the museum's president and chief executive officer. His appointment as The Met’s top leader received attention in the museum community, as the higher-ranking role in a museum is traditionally the Director. During Weiss’ tenure, the museum has set attendance records for three years straight. Following high operating deficits, which led to staff cuts, the Museum improved revenue and set fundraising records, and has said it will have a balanced budget by 2020. When Weiss arrived at The Met, he discovered the museum faced significant operating deficits, so he chose to sequence large capital projects the Museum was planning. He moved ahead with renovations of the skylights over the European Paintings galleries, and paused the modern wing project. After The Met made progress on balancing the budget, Weiss announced moving ahead with major renovation of galleries covering art from Africa, Oceania and the Americas. Weiss advocated for changing The Met’s admissions policy for the first time in 50 years—which was controversial, and has ended up being described as highly successful. Weiss was the first leader to speak out on several important issues touching museums, including the Trump administration decision to pull out of UNESCO. On October 12, 2017 Weiss voiced, on behalf of the museum: "President Trump’s decision to withdraw from UNESCO undermines the historic role of the United States as a leader in this effort and weakens our position as a strong advocate for cultural preservation. Although UNESCO may be an imperfect organization, it has been an important leader and steadfast partner in this crucial work." Weiss has also taken positions on Saudi funding, in the wake of the murder of the Washington Post journalist, and funding from the Sackler family.
Weiss serves on the Board of the Samuel H. Kress Foundation. He is also a member of the Board of Directors of The Posse Foundation, the Library of America and of the Advisory Board of the Yale School of Management.
Works
Weiss has published different books and in June 2017, signed a contract with PublicAffairs for his new book "". The book will be published in November 2019.