In July, after registering no more than 4% in public opinion polls over several months, Mammoliti withdrew from the mayoral contest in order to stand for re-election as a city councillor.

The NDP won a majority government and Mammoliti was appointed as parliamentary assistant to the minister responsible for the provincial anti-drug strategy on October 1, 1990.

In 2018, Mammoliti announced he would re-enter provincial politics, and seek the Progressive Conservative Party of Ontario nomination in Brampton Centre.

[5] Thirteen days later he decided against such a run, citing his "difficult decision to continue to represent the City of Toronto" by remaining in municipal politics.

At around the same time, he quit the NDP and joined the Liberal Party (this decision did not affect his standing on council, as all Toronto councillors are elected as independents).

On July 28–29, 2011, the executive committee of Toronto City Council heard deputations by 169 Torontonians on the hundreds of millions of dollars in budget cuts suggested by KPMG consultants.

[9] In response to the late July executive committee meeting, Mammoliti launched a "Save the City...Support the Ford Administration" Facebook group in August 2011.

[10] He indicated that he created the group so that the "taxpayer" would have an opportunity to comment on how municipal taxes should be spent in Toronto and stated: "If you smell like someone who can be a part of the Communist Party you’re not going to be welcome on the site.

[14] The integrity commissioner released a report to Toronto City Council detailing two fundraisers held for Mammoliti which paid him $80,000.

On July 9, 2014, Toronto City Council voted to suspend Mammoliti and withhold his salary for three months for holding the fundraisers.

[16] In a 2017 episode of the television series Political Blind Date, Mammoliti and Matt Brown discussed their differing perspectives on the issue of safe injection sites.

His platform included building a floating casino, introducing a municipal lottery, reversing tax increases he had he previously voted for, creating a red light district for prostitution, an 11pm curfew for children under the age of 14 and giving guns to by-law enforcement officers.

[20] He called for cars to be banned from the Gardiner Expressway, converting the thoroughfare into a garden and implementing road tolls[21] on other major routes.

After campaigning for six months without polling above single digits, Mammoliti announced his withdrawal from the contest on July 5, 2010, in order to run for re-election as a city councillor.

In June 2010, Mammoliti and fellow councillor Rob Ford co-sponsored a motion to deny city funding to the Toronto Gay Pride Parade if it didn't ban the group Queers Against Israeli Apartheid (QuAIA) from participating.

[29] During the lead-up to the 2018 Toronto municipal election, Mammoliti was criticized by his constituents for likening social housing residents with criminal records to cockroaches in an appearance on the right-wing website The Rebel Media.

[30] In an election ad in September 2018, Mammoliti was shown as ready to swing a sledgehammer under the words, "Saving our community begins with knocking down social housing".