On 18 December 2014, Barbara Thiel was elected by the State Parliament of Lower Saxony as State Commissioner for Data Protection pursuant to Article 62 of the Constitution of Lower Saxony and was appointed by the State Government for a period of eight years with effect from 1 January 2015. Her term of office ended on 30 June 2023 after a statutory extension of six months.

Barbara Thiel grew up in Salzgitter. After training in the senior civil service in local government, she studied law at the University of Göttingen, where she passed her First State Examination in Law. She completed her legal clerkship and second state examination in law in Lower Saxony, and subsequently worked for the Lower Saxony Ministry of the Interior and the Lower Saxony State Court of Audit, among others. In 2002, she moved to local government, first as first district councillor in the district of Wolfenbüttel and from 2007 to 2014 as head of department in the Hanover region. During this time, she was responsible for human resources, finances and all IT in the administration, among other things.

Barbara Thiel is a lecturer at the University of Göttingen, the author of numerous publications, lectures and two commentaries on the GDPR and the BDSG, and she is a member of the editorial advisory board of the ZD and the advisory board of the PinG.