His Father first bought shares in Tata Sons in the 1930s, a stake that currently stands at 18.4%, making Mistry the largest individual shareholder in Tata Sons, which is primarily controlled by the charitable Tata Trusts.
In 2003, Pallonji gave up his Indian citizenship to become an Irish citizen "on the basis of his marriage to an Irish-born national", Pat (Patsy) Perin Dubash, who was born in September 1939 in Hatch Street Nursing House in Dublin. He remains in residence in Mumbai.
A short biography of Mistry was written in a 2008 book by Manoj Namburu titled The Moguls of Real Estate.
His son, Cyrus, was chairman of Tata Sons from November 2011 to October 2016. Within the Tata Group he is known as the Phantom of Bombay House for the quiet but assured way he commands power around the Mumbai headquarters of the Tata empire.
The Mistrys own a substantial construction company, Shapoorji Pallonji. Shapoorji, the group patriarch and Pallonji's Father, built some of Mumbai's landmarks around the Fort area – the Hong Kong & Shanghai Bank, the Grindlays Bank, the Standard Chartered Bank, the State Bank of India and the Reserve Bank of India buildings.
He was awarded the Padma Bhushan in January 2016 by the Government of India for his contributions in the field of trade and industry.