NDP nomination and 2006 Parkdale–High Park by-election

When Gerard Kennedy stepped down as the Member of Provincial Parliament (MPP) for Parkdale–High Park, the NDP was not expected to win the seat.^[19] Two candidates came forward to contest the NDP nomination: DiNovo and former journalist, and at the time of the nomination, the executive director of the Canadian Arab Federation, Mohamed Boudjenane.^[19] The spirited campaign that followed lasted about a month, with both sides signing up large numbers of new members.^[19] Boudjenane was endorsed by United Steelworkers of America president Leo W. Gerard and the former president of the Ontario NDP, Andre Foucault. DiNovo had the support of NDP stalwart Michael Lewis^[20] and many members of the riding's executive. The nomination meeting took place in the middle of a heat wave on the evening of 17 July 2006, in the Parkdale Collegiate Institute auditorium.^[21] The sweltering auditorium was filled with over 300 people, most of them delegates. DiNovo defeated Boudjenane with a comfortable margin.^[21][22]

DiNovo defeated Liberal Sylvia Watson in the 14 September 2006 by-election to replace Gerard Kennedy in the Legislative Assembly of Ontario. She officially took her seat in the Assembly on 25 September.

During the campaign, DiNovo acknowledged having been both a "street kid" and a user of recreational drugs in her youth. She was criticized for this by Watson's campaign.

The Liberals alleged that DiNovo endorsed the church ordination of pedophiles and axe murderers in Qu(e)erying Evangelism, when in fact she did not, and took DiNovo's past comments about Canadian murderer Karla Homolka out of context, saying the comments compared Homolka to a Christ-like figure, where instead they were used in reference to the dangers of scapegoating. The Liberals also did not mention DiNovo's expression of sympathy for Homolka's victims' families and the undue suffering she believed the media circus surrounding Karla was causing them. Many accused the Liberals of conducting a smear campaign.^[23]

Poverty and the $10 minimum wage campaign

In October 2006, a Toronto Star column by Carol Goar said DiNovo had brought a new clarity and assertiveness to the NDP caucus' voice in the Ontario Legislative Assembly.^[24] Since entering the Assembly, DiNovo has approached a variety of poverty-related issues, including raising minimum wage and welfare rates in the province, creating more affordable housing and ending the government's tax clawback of the federal child benefit supplement.^[24]

Earlier in the year DiNovo had shared her experiences of drugs and poverty as a 15-year-old, in a TV interview first shown on VisionTV on 9 March 2006. She said "I know what its like to live on the streets ... street kids are not bogey men, they are just poor".^[25]

39th Parliament election and sessions

DiNovo retained her seat in the 2007 Ontario general election and began serving her term in the Ontario Legislature's 39th Parliament sessions. The Parkdale–High Park campaign featured the same three major candidates as the 2006 by-election, with Watson and David Hutcheon representing the Liberals and the Progressive Conservatives respectively. She increased the margin of victory from the 2006 by-election.^[26]

When Howard Hampton announced he was stepping down as leader of the Ontario New Democratic Party in June 2008, DiNovo was one of four MPPs, along with Michael Prue, Peter Tabuns and Andrea Horwath, whose names were suggested by party insiders as potential candidates in the 2009 Ontario NDP leadership convention.^[27] However, she was quoted in the Toronto Star a few days later as saying that she was unlikely to be a candidate,^[28] and she subsequently endorsed Tabuns for the leadership.

She became the Third Deputy Chair of the Committee of the Whole House, also known as the "Deputy Speaker", on 26 March 2009.^[29] On 16 September 2009, she was promoted to Second Deputy Chair of the Committee of the Whole House.^[29]

In 2012, DiNovo succeeded in getting Toby's Act passed, an amendment to the Ontario Humans Rights Code to include gender identity and gender expression–the first of its kind in North America.^[30]

During the 39th Parliament, DiNovo introduced many other bills covering such concerns as repealing dog-breed specific legislation,^[31] inclusionary housing,^[32] and safe bicycle passing guidelines.^[33] She also co-sponsored an all-party bill, that became law, calling for the commemoration of the Ukrainian genocide known as the Holodomor on the 15th of November each year in Ontario.^[34]

40th Parliament election and sessions

DiNovo ran for re-election in the 2011 Ontario general election. Her main opponent was the Liberal Party candidate Courtney Pasternak. Indications from polling in the summer suggested that Pasternak might win; but on election day, DiNovo easily won re-election.^[35] Like other districts bordering on the rail link to Pearson Airport from Union Station, she successfully made the project's potential environmental impact on the community as the main issue in the campaign, by coming out against the Liberal's proposal to first use diesel trains and then eventually electrify the line at some future date.^[35]

41st Parliament election and sessions

DiNovo was narrowly re-elected in the June 2014 election. She defeated Liberal candidate Nancy Leblanc by 525 votes.^[36] She avoided the Liberal success in Toronto that saw three out of four other NDP incumbents go down to defeat.^[37]

As of July 2014, she was the party's caucus chair and the critic for urban transportation, LGBTQ, and Greater Toronto Area issues.^[38] She became the first ever LGBTQ critic in Ontario; former Xtra! journalist Andrea Houston was a staffer.

DiNovo has been an outspoken advocate for cyclist and cyclist safety, including her "one-meter rule", which the government finally passed as part of their larger transport bill in 2015.

In 2015 DiNovo's Bill 77, which prohibits conversion therapy for youth (therapy intended to prevent young people from identifying as LGBTQ) passed and became law. The legislation also delisted conversion therapy from OHIP. Following the introduction of the bill, President Barack Obama called for a ban of the practice in the United States. Manitoba has tabled legislation to ban the practice as well.

DiNovo also tabled Bill 137, Cy and Ruby's Act (Parental Recognition), 2015 which seeks to amend the Children's Law Reform Act and the Vital Statistics Act to be more LGBTQ inclusive so that LGBTQ parents are also recognized as parents under the law. In December 2015, Bill 137 passed Second Reading with all party support and is currently waiting to be reviewed by the standing committee on regulations and private bills.

DiNovo successfully proposed a bill to recognize Post-Traumatic Stress Disorder (PTSD) as a work place injury for first responders fast-tracking their Workplace Safety and Insurance Board benefits. After seven years, four bills and one second reading, the government introduced legislation in February 2016.

Similarly, DiNovo tabled her bill on inclusionary zoning (for affordable housing) five times over eight years, passing second reading twice. In May 2016, the government introduced housing legislation that included inclusionary zoning.

In a 2017 episode of the television series Political Blind Date, DiNovo and Marie-France Lalonde discussed their differing perspectives on the issue of criminal justice and corrections.^[39]

Federal party leadership bid

In the wake of the October 2015 federal election, in which the federal NDP fell from second to third place, DiNovo was critical of Tom Mulcair's leadership of the federal NDP and of what she viewed as the party's centrist course under his leadership.^[40] DiNovo openly supported a leadership review of Mulcair's stewardship of the federal party at the party's April 2016 convention and called for the NDP to reaffirm its socialist principles. After Mulcair was defeated in the leadership review, DiNovo announced she would run as an "unofficial candidate" in the 2017 federal NDP leadership election on June 7, 2016 rather than pay the required fee of $30,000. She also announced that she will not be running for re-election to the Ontario legislature in the 2018 provincial election.^[41][42] However, on June 13, 2016, she announced that her candidacy will be moving from unofficial status to official status, stating that her campaign will begin fundraising when the leadership election rules are finalized in July 2016.^[43] DiNovo announced on August 2, 2016 that she was withdrawing from the race due to health reasons after having recently suffered two small strokes.^[44] She later endorsed Manitoba MP Niki Ashton's campaign.^[45]