Kosinski grew up in Wallingford, Connecticut, and got her BA from Yale University and her MA and PhD degrees from the New York University Institute of Fine Arts. After being an intern and curatorial assistant at the Guggenheim Museum, she became a curator for the Bruce Museum in Greenwich, Connecticut, and for the private collection of cubist art left by Douglas Cooper in Basel, Switzerland. From 1995 to 2008 she worked at the Dallas Museum of Art, where she became senior curator of painting and sculpture, then was appointed director at The Phillips Collection. She was also an independent curator for the Kunstmuseum Wolfsburg, the Kunstmuseum Basel, and the Royal Academy of Arts.
President Obama appointed her in 2012 to the National Council on the Humanities, an advisory council to the National Endowment for the Humanities. She is a member of the US-China Forum on the Arts and Culture.
- Trescott, Jacqueline (5 December 2007). "Phillips Collection Taps Dallas Curator To Succeed Director". The Washington Post. Retrieved 13 December 2012.
- "Dorothy Kosinski". US-China Forum on the Arts and Culture. Retrieved 13 December 2012.
- Rubell, Mera (18 May 2010). "The Phillips' Female Force". Washington Life Magazine. Retrieved 13 December 2012.
- "President Obama Announces More Key Administration Posts". White House Office of the Press Secretary. 10 July 2012. Retrieved 13 December 2012.
- Kosinski at The Phillips Collection website