The President who brought progressivism into law in America with the creation of the American safety net. Progressivism as a movement and a political philosophy had been around much longer than that in America. Going back to the late 1890s or even further than that. But President Roosevelt was the first President to get those programs passed into law.
And what makes FDR different from todays what I call so-called Progressives, was that FDR wanted to save American capitalism, not try to end to and replace it, which is something else. Which was what the New Deal was about which was to have a safety net that people could turn to. To make up for the shortfalls of capitalism like people being out-of-work.