He enrolled at the University of Toronto and graduated with a master's degree in Economics in 1942.(?)

He immediately returned to Europe to join the Allied war effort serving in the Netherlands Forces as an economist, and helped bring the financial situation back in balance.

Hartog asked to be demobilized in Canada after his tour of duty, and returned to settle in Canada in 1946, when he founded Kindred Industries Limited, which became a multi-national corporation eventually employing 1,400 people.

In the 1970s, Hartog merged Wallaceburg Brass with Kindred Industries, becoming the founding Chair and CEO of Waltec Incorporated in Midland.

The Georgian College Robbert Hartog Midland Campus is named after him.