Hillyer won a nomination to run in a Saskatchewan provincial election under the Saskatchewan Party banner in a Reginaelectoral district. He decided to drop out after he was diagnosed with leukemia. He made a political comeback running for a seat to the House of Commons of Canada in the 2011 Canadian federal election. He contested the electoral district of Lethbridge as a Conservative candidate and held for his party with a large majority. His decision to not attend any candidate forums after his first was a controversial topic in the riding. Hillyer's absence prompted a local Lethbridge newspaper to dub Hillyer "The Man Who Wasn't There". He was also accused of inflating his credentials in campaign literature by emphasizing his graduate education but not mentioning that the institution where he studied—George Wythe University—is non-accredited. In December 2011, Hillyer stated in the House of Commons that he intended no offence when he made gunshot gestures with his hands as he voted to scrap the Canadian Firearms Registry. In promising not to make hand gestures in the Commons in the future, Hillyer suggested that "if people were offended they should blame whoever posted the six-week-old video on the anniversary" of the École Polytechnique massacre. In March 2012, Hillyer was caught on camera "rolling his eyes dramatically" in the House of Commons during a speech by NDP MP Pat Martin.
Between the 2011 and 2015 federal elections, the electoral boundaries in southern Alberta were changed. Raymond, where Hillyer lived, was moved from the Lethbridge riding to Medicine Hat, which was expanded and renamed Medicine Hat—Cardston—Warner for the 2015 election. In 2014, upon learning that Medicine Hat MP LaVar Payne would not be running for reelection, Hillyer decided to seek the Conservative nomination for Medicine Hat—Cardston—Warner rather than seek re-nomination for Lethbridge. In July 2014, Payne announced that he would not be endorsing Hillyer for the 2015 federal election, citing Hillyer's poor service of his constituents: "I have no problem saying that I won’t be endorsing Jim just because of the fact that I know he hasn't served his own riding, and I don’t want that to happen here.... I know that he has not serviced his riding very well. I've had people from Lethbridge, Cardston area and Warner area talk to me about the whole thing, so I certainly won’t be endorsing Jim." However, Hillyer still won by a nearly 4-to-1 margin over his nearest opponent.
Health and death
Hillyer had survived leukemia after receiving a bone marrow transplant in 2003. In February 2016, Hillyer underwent surgery for a serious leg bone infection, the latest in a series of complications resulting from breaking his leg while skiing three years previously. Hillyer returned to Ottawa after recovering from surgery to vote on the 2016 Canadian federal budget. After complaining of feeling unwell the previous day, Hillyer, aged 41, was found dead in his Ottawa office on 23 March 2016. An autopsy confirmed the cause of death to be cardiomyopathy which may have been caused by either a pre-existing heart condition or caused by chemotherapy he underwent a decade before.
