He is a Member of the Supreme Council and Division Chief of Padang Terap of the United Malays National Organisation (UMNO), a component party of the BN coalition.

[2] Mahdzir's tenure as Menteri Besar came to an end after his BN Kedah state government was defeated in the 2008 election by the Pakatan Rakyat (PR) opposition coalition led by the Pan-Malaysian Islamic Party (PAS).

[3] Mahdzir became Barisan Nasional's opposition leader in the state assembly before moving to federal parliament in the 2013 election, winning the seat of Padang Terap from PAS.

[4] Over a period of about 17 months between 2015 and 2017, as Minister of Education, Mahdzir was pressured to award a contract for the provision of electricity to rural Sarawak schools to Jepak Holdings.

[5][6] In late 2015, Saidi Bin Abang Samsudin and Rayyan Radzwill bin Abdullah proposed to the Ministry of Education that it award their company, Jepak Holdings Sdn Bhd, a contract to replace other contractors for the provision of maintenance of diesel electric generators at rural and interior Sarawak schools and install a hybrid solar voltaic system for RM1.25 billion.