[6] She holds a Bachelor of Arts in Social & Political Thought and History and a Certificate in Refugee and Migration Studies, both from York University.

[11] In 2005, Leslie attended the United Nations Framework Convention on Climate Change in Montreal to present on the issue of energy poverty.

Leslie launched an initiative as the NDP's health critic to propose a national pharmacare plan to pay for expensive prescription drugs.

[20] She also introduced a private member's bill to create a national strategy for suicide prevention, which has garnered the support of some municipal councils.

[21] She was also noted for being "well-briefed on the controversy surrounding Assisted Human Reproduction Canada last spring, when several board members resigned amid allegations of lack of transparency over spending.

Leslie re-introduced the NDP's Climate Change Accountability Act in the House of Commons in June 2011[23] after it was defeated by the unelected and appointed Senate in 2010.

[24] In 2012, Leslie was the target of hate mail after The Hill Times misattributed a quotation critical of ATV drivers from Green Party leader Elizabeth May to the NDP MP.

[31] However, the World Wildlife Fund Canada temporary role ended in June, when she was expected to work back home in Halifax, where her partner was awarded a Postdoctoral Fellowship at Dalhousie University.

[33] After Tom Mulcair was ousted as NDP leader, Leslie was considered a candidate for the New Democratic Party leadership election to replace him, she declined, saying that she was tired and out of energy and that she could not see herself running again before 2019.

[37] In her essay, Leslie expressed her belief in her generation's recognition of the complexity of social change, and her style of politics that recognizes the need for robust community participation as well as representation in parliament.

In December 2010, she was voted as the favourite "Up and Comer" on Parliament Hill[38] and was picked as one of the year's top MPs by columnist David Akin.