Diesner-Wais was elected a member of the Schrems municipal council in 1990. Between 1995 and 2005 she was a city councilor, then again a councilor, and currently again a city councilor.[1]
Diesner-Wais was sworn in as a member of the Federal Council on 24 April 2003 and was secretary of the Federal Council from 1 January 2006 to 30 June 2006. After the 2013 Austrian legislative election, Diesner-Wais moved from the Federal Council to the National Council.[2] She was able to defend her mandate in the elections of 2017[3] and 2019.[4]