In 2014, Mothapo was elected to the National Assembly of South Africa from the ANC's Limpopo list.
[3][4] Mothapo was elected to chair the Portfolio Committee on Justice and Correctional Services on 9 October 2018.
[5] As chair of the Justice and Correctional Services portfolio committee, the portfolio committee rejected a request by the opposition Democratic Alliance (DA) to expedite procedures to remove Public Protector Busisiwe Mkhwebane from office as a similar process was instituted by the DA in the North Gauteng High Court and the committee believed that it was premature to run a parallel process.
[6] Mothapo was 17th on the ANC's list of parliamentary candidates from Limpopo for the 2019 general election.
[2] Mothapo was not an ANC parliamentary candidate in the 2024 general election and left parliament.