His father, Toyo Erodikromo, was an immigrant from Java, Indonesia while his mother, Siti Aminah binti Mohd Taib, is of Malay ethnicity.

[6] Khir was active in the youth wing of the United Malays National Organisation (UMNO), serving on its executive council.

In 2000, at the age of 35, he became the Menteri Besar of Selangor at the insistence of Prime Minister Mahathir Mohamad, following the resignation of Abu Hassan Omar.

His young age led to allegations, which he denied, that he had dyed his hair grey to give voters the impression that he was older.

Khir contested for the UMO Youth Chief post in 2008, but eventually placed second in votes after Mukhriz Mahathir and lost the election to Khairy Jamaluddin.

[9] He resigned as the opposition leader in December 2010, after he was charged with corruption over allegations that while he was the Menteri Besar, he was sold a lavish mansion for less than its market value.

[14] On 28 September 2022, he stated that he was prepared to make a political comeback by contesting for the seat and regaining it from the present Sungai Besar MP Muslimin Yahaya of BERSATU and PN, who was also the Deputy Minister of Entrepreneur Development and Cooperative.

The opposition criticised Khir Toyo for approving housing project in squatters' area and forcing the residents to move out from their illegal homes.

A total of 1,708 squatter families were shifted following court cases, resettled to the North Gombak Orang Asli settlement and planned villages, it said.

A special investigative team which was set up for the purpose would probe how certain senior officers of the corporation were holding 30% shares in a subsidiary.