He was called to the bar in 1999.[3][4] He worked in civil litigation with Calgary legal firm Rooney Prentice[4] before working for the Canadian Taxpayers Federation conservative advocacy organization[3][5] and as the executive director of the Canadian Constitution Foundation.[6]
Carpay is the president of Justice Centre for Constitutional Freedoms,[7] which he founded in 2010.[8] The organisation describes its mission to defend "the constitutional freedoms of Canadians through litigation and education."[9]
Carpay has written columns for The National Post, The Calgary Herald, and Huffington Post.[5]
In 2021, Carpay supported seven churches in their legal bid to fight COVID-19 public health regulations, and during that time, he hired a private investigator to follow Manitoba chief justice Glenn Joyal.[9][10] Those actions prompted a misconduct complaint from human rights lawyer Richard Warman and critique from University of Alberta's vice dean of law Eric Adams, who described the action as a "tremendous, tremendous lapse of judgment."[9] Carpay took indefinite leave from the JCCF in July 2021, before being reinstated as president in August 2021.[9] Six of the nine members of the board of directors resigned following his reinstatement.[6] An arrest warrant for was issued by Winnipeg Police in December 2022, prompting Carpay to present himself to Calgary Police Service, where he was arrested on December 30[11][12] before being released the next day.[13] Carpay has been charged with "intimidation of a justice system participant and attempting to obstruct justice."[7] The Law Society of Manitoba will bring professional misconduct against Carpay at a February 2023 hearing in Winnipeg.[7]
On August 21, 2023, The Law Society of Manitoba barred from practising in the province and ordered him to pay $5,000. In his statement Carpay said, "I fully acknowledge that my instructing surveillance of Chief Justice (Glenn) Joyal was in violation of my professional obligations as a lawyer to the court and to society."[1] On September 2, 2025, Carpay was disbarred by the Law Society of Alberta for the same reasons as in Manitoba.[14][15]