Finance minister

In 1940, he was promoted to Minister of Finance. He held that position for the duration of World War II during a period of massive expansion in expenditure due to the war effort, described as a "transformation of the Canadian tax system" by historian Colin Campbell.^[1] Under his direction, the minimum income required to pay income tax was push dramatically downward, effectively changing income tax from a "class tax" on the wealthiest 300,000 or so Canadians to a national tax imposed on millions of average workers, and directly deduced from their checks.^[1] The revenue generated from income tax during this era expand by nearly 1000%.^[1]

He also led the Victory Bond campaign, brought in wage and price controls in 1941, and deal with several currency crises.^[1] He was also known for his call for personal sacrifice by civilians during the war and led by example by giving up his car and riding the streetcar to Parliament Hill.^[1] In 1945, despite the taxes he had imposed on the general public, he was rated the most popular cabinet minister in the cabinet.^[1]

He was recognized for his service in 1946 when he was appointed to the Imperial Privy Council, and given the honorific of "Right Honourable".

Minister of justice

The same year, he became Minister of Justice. He served in that position until he retired from politics in 1948.