Khair joined the University of Dhaka as a lecturer on 1 January 1990.[7] She was promoted to Assistant Professor in 1994.[7]
Khair was promoted to Associate Professor in 2002.[7] She joined Eastern University as an adjunct professor. She was promoted to full professor at the University of Dhaka in 2005.[7]
In January 2009, Khair was appointed chairman of the Department of Law at the University of Dhaka.[7] She served as the chairman till 2011.[8] She received the University Grants Commission Award in 2011.[7] She became a deputy executive director of Transparency International Bangladesh in 2013.[7] She served as the editor of the Dhaka University Law Journal.[9]
Khair was appointed an advisor to the executive committee of Transparency International Bangladesh in 2017.[7]
In January 2020, Khair signed a letter protesting the legal case against the editor of Prothom Alo Matiur Rahman over the death of school student at an event of the Prothom Alo.[10][11] She signed a statement in 2021 demanding the release of Rozina Islam, a reporter of Prothom Alo.[12] She called on the government to renew the registration of human rights organization Odhikar in 2022.[13]
Following the fall of the Sheikh Hasina led Awami League government, Khair was made a member of the Constitution Reform Commission of the Muhammad Yunus led Interim government in October 2024.[14]