Dhillon has lived in Brampton, Ontario for most of his life. He has a degree in Business Administration from Lakehead University, and helped found a family-owned business in Mississauga after his graduation. He has done fundraising work for the Brampton Food Bank, and led a local initiative to send supplies to eastern Ontario during the ice storm of 1998. Dhillon worked as a constituency assistant to federal Liberal Member of Parliament (MP) Gurbax Singh Malhi for five months after the 1993 federal election, and then worked as an as executive assistant to Liberal MP Colleen Beaumier for just over nine years.
Dhillon first ran for the Ontario legislature in the 1999 provincial election, and losing to high-profile Progressive Conservative cabinet minister Tony Clement in the newly-created provincial constituency of Brampton West—Mississauga. He ran again in the 2003 election, and this time defeated Clement by 2,512 votes. Most political observers considered this to be a significant upset. Strong support from the constituency's Indo-Canadian community was a factor, as was a provincial swing to the Liberals.
Dhillon was 34 years old at the time of his election, and his second child was born during the campaign. He was appointed as parliamentary assistant to the Minister of Government Services on September 20, 2006.
In 2004, Dhillon was credited by local residents with saving Knights Table, a non-profit diner that provides meals for Brampton's poor and homeless. According to a Toronto Star report, Dhillon introduced the diner's management to Jaswant Singh Birk, who in turn provided the establishment with a generous lease after its previous contract expired.
In December 2006, he introduced a private member's bill to protect transient workers from exploitation by hiring agencies. The bill was endorsed by the Toronto Star newspaper the following week.
Dhillon took part in an Ontario government business mission to India in January 2007.
Information from these pages has been integrated into this article.
All election information is taken from Elections Ontario. Expenditure entries are taken from official candidate reports as listed by Elections Ontario. The figures cited are the Total Candidate's Campaign Expenses Subject to Limitation, and include transfers from constituency associations.