After a year as a toddler living with his grandparents in India, Singh spent his early childhood in St. John's and Grand Falls-Windsor, both in Newfoundland and Labrador, before relocating with his family to Windsor, Ontario. Singh has publicly discussed suffering sexual abuse as a child, as well as having a father who was alcoholic and abusive. From Grade 6 to 12, Singh attended Detroit Country Day School in Beverly Hills, Michigan. Singh went on to obtain a Bachelor of Science degree in biology from the University of Western Ontario in 2001 and a Bachelor of Laws degree from York University's Osgoode Hall Law School in 2005. He was called to the Bar of the Law Society of Upper Canada in 2006. Singh has two younger siblings, brother Gurratan and sister Manjot, who were both born during the family's time in Newfoundland. Gurratan, who is also a lawyer and politician, has been described as Jagmeet's "secret weapon". Gurratan Singh was elected to the Legislative Assembly of Ontario in the 2018 Ontario election, representing the riding of Brampton East. Singh worked as a criminal defence lawyer in the Greater Toronto Area before entering politics, first at the law firm Pinkofskys, then at his own practice, Singh Law, which he established with Gurratan. During his time as a lawyer he offered free legal rights seminars across Ontario and provided "pro bono" legal counsel for people and community organizations in need. In a "Toronto Star" article published January 9, 2012, Singh stated that his background in criminal defence contributed to his decision to enter politics, particularly his work advocating for the protection of rights entrenched in the Canadian Charter of Rights and Freedoms. Singh provided "pro bono" consulting to an activist group that protested the visit to Canada of Kamal Nath, the Indian trade minister who had persecuted Sikhs and had allegedly led armed mobs during the 1984 Delhi pogrom. After failing to get their views heard, Singh was inspired to run for office by the activist group so their concerns could be better represented. Singh began his political career with his decision to run for Member of Parliament in the 2011 federal election as the NDP candidate in the riding of Bramalea—Gore—Malton. During the election, Singh stopped using his surname, Dhaliwal (which is connected to caste), because he wanted to signal his rejection of the inequality inherent in the Indian caste system. Instead, he chose to use Singh, which reflects the spiritual belief in an egalitarian society where all enjoy equitable access to rights and justice.