In the 1930s, the Mansha family had migrated to Bengal from Punjab. After 1947 Partition of British India, the family returned to Punjab, Pakistan. Mian Muhammad Mansha's Father started a cotton ginning Business which later became the Nishat Textile Mills. Mansha was born in Lahore to a wealthy Chinioti Punjabi family, his privileged upbringing allowed him to enjoy an early Business education at the University of Punjab in Lahore. Although his childhood was spent in Faisalabad from where he also started his career as one of the most prominent industrialists of Pakistan. Nishat Textiles Mills was started in 1951 by his Father and uncles. His Father died one year after he returned from London after finishing his studies there in 1968. Mian Muhammad Mansha joined the family Business in 1969 and eventually he split with his uncles and took over the family Business. He was worth US $2.5 billion till 2013. Apart from making large acquisitions, he was simultaneously expanding his Nishat Textiles segment. Nishat Textiles Mills is Pakistan's largest fabric Manufacturing mills.

After 1979, Mansha set up Pakistan's largest textile complex of seven mills in Nishatabad in the city of Faisalabad. In later years, another textile complex followed in Chunian near Lahore.

Mansha's conglomerate greatly benefited from the privatization drive by the governments of the 1990s. Through this period, he made a number of acquisitions and buy-outs, including engineering at least one hostile takeover. When the dust settled, Mansha had acquired a controlling position in Adamjee Group, the country's largest non-life insurer. Nishat Mills also acquired two thermal plants near its DG Khan Cement Plants located in Dera Ghazi Khan District, Punjab, previously owned by the Saigol family. Business analysts in Pakistan reportedly said that the acquisition of two thermal plants would ensure uninterrupted power supply to D. G. Khan Cement Plants for the Nishat Group. While going through these large acquisitions, he was simultaneously expanding his Nishat Textiles segment, Nishat Textiles Mills is Pakistan's largest fabric Manufacturing mills.

Mansha is currently on the board of various prominent institutes in Pakistan and is one of the most powerful and influential people in the country. He was awarded the Sitara-e-Imtiaz civil award by President of Pakistan Pervez Musharraf on 23 March 2004. One of Mansha's companies, Nishat Textile Mills Limited, is the largest exporting entity in Pakistan.

Mansha was named richest Pakistani in 2005 by Daily Pakistan with net worth of ₨263.3 billion (equivalent to ₨810 billion or US$7.7 billion in 2013). In March 2010, Mansha was mentioned in Forbes billionaires list.But his fellow billionaires have indicated that his net-worth is well over 20 billion USD as of 2017 excluding fixed assets which are in excess of 15 billion USD.

MCB Bank, in 2008, started a partnership with Maybank of Malaysia. Maybank now has a 20% share in MCB Bank. In 2009, Mian Muhammad Mansha, chairman MCB Bank, said that his efforts were successful in continuing to bring foreign investment to Pakistan and that his bank had already brought 970 million U.S. dollars' investment into the country from Malaysia following a deal with May Bank, Malaysia. He was selected for a special Lunch with the UK Financial Times newspaper. According to Forbes listings in 2010, he was the 937th richest person in the world & no. 1 in Pakistan.