[5] In 1995, and again in 2000, Donnelly swam the length of the 1,325 km Fraser River, from Mount Robson Provincial Park to Vancouver, ending in False Creek.

[13] The 43 year-old Donnelly entered federal politics after his local member of parliament Dawn Black vacated her seat in April 2009.

[17] The by-election was called for November 9 and Donnelly, who was supported by campaign visits by party leader Jack Layton, and Dilworth were considered the front-runners.

He sponsored two amendments to the Criminal Code, both of which Dawn Black had previously introduced in the previous parliament: Bill C-520 would have added the offence of luring a child to those offenses prosecutable in Canada even if committed outside Canada, and Bill C-521 would have expanded the offence of luring a child to include all means of communication rather than solely through a computer.

[22] In March 2010, he introduced Bill C-502 that would prohibit oil tankers in the Dixon Entrance, Hecate Strait and Queen Charlotte Sound.

In May 2010, he introduced Bill C-518 which proposed to amend the Fisheries Act to require commercial finfish aquaculture only take place in closed containment facilities.

He was re-appointed as critic on Fisheries and Oceans by party leader Jack Layton in the NDP shadow cabinet of the 41st Canadian Parliament.

While none of the bills again advanced far enough to be voted upon, the two proposed amendments to the Criminal Code regarding luring a child were adopted in the Safe Streets and Communities Act.

[29][30] Donnelly subsequently faced criticism for his role in the spread of the false information regarding Alan Kurdi's family's nonexistent refugee application.

[33] On September 10 the Ottawa Citizen reported that: "Abdullah Kurdi’s brother Mohammad and his family were named in a G5 refugee resettlement application, while simultaneously, Abdullah and his now-dead wife and children were included and named along with Mohammad’s family in a lengthy set of correspondence, over a period of months, to Citizenship and Immigration Minister Chris Alexander and senior CIC officials.

With a reduced number of MPs, party leader Tom Mulcair appointed Donnelly to be the NDP critic for Fisheries, Oceans, and the Canadian Coast Guard,[37] a post he previously held in 2009-2012 and since acted as deputy to.

In the 42nd Canadian Parliament he again sponsored the private member bill C-228 which proposed to amend the Fisheries Act to require commercial finfish aquaculture only take place in closed containment facilities.