"Between FDR's inauguration and 1936, production doubled. Unemployment fell from 25 percent to under 10 percent in that period. Incidentally, according to James Galbraith's recent testimony before the Senate Committee on Banking, the charge that the New Deal did not increase employment massively rests on a truly absurd maneuver: the conservative critics don't count federal relief (Civil Works Administration, Work Projects Administration, and Public Works Administration) employment. As Galbraith pointed out, this is like counting a construction worker building a military airplane under a government contract with a private company as employed, while categorizing a worker building the Lincoln Tunnel and paid directly by the federal government as unemployed."
This article is a great beginning-overview of the New Deal and what worked, what didn't, and why. The reasons why are exactly the opposite of the reasons given by the laissez-faire capitalists known as the libertarians. Under funding and discrimination are the main reasons that aspects of the New Deal didn't work nearly as well as they would have otherwise.
I too have mentioned that information from James Galbraith before. He's not the only one to have made it a bit more prominent either. However, the facts he cites are drowned out by Glenn-Beck airheads and those who actually know the truth (such as Rupert Murdoch) but wish to keep it suppressed because, otherwise, the people might get ideas – right ideas about cooperating together on the level rather than being cutthroat, dog-eat-dog hyper-capitalists.
In addition, it must be understood that WWII was Military Keynesianism. Keynesianism worked very well. The only mistake was that it was employ for war when employing it long before war would have even precluded the war.
Two other notable aspects not mentioned in the linked article are that 1) much of the hiring was done by private contractors when it should often have been done directly by the government to speed it up and 2) the private sector fought tooth and nail against government run skilled-labor training. The military provided high-skills training that worked only too well. Now if that level of publicly funded training were supplied to everyone to the extent each is able to absorb the training and employ it, there wouldn't be the unemployment we have now and there wouldn't be the economic depression either.
Lastly, I've heard over and over how people should not become dependent upon the government. Interestingly enough, this often comes from people who have been in military service or who have otherwise taken goods and services supplied communally or collectively if you will. The idea of the rugged individualists has its place, but there is absolutely nothing wrong with interdependence in other settings. From a Christian perspective, the first Christians very much depended upon each other and rightly so. Never mind those twisted arguments suggesting that those Christians only did it because of the particular circumstances and would not have otherwise. They did it because given and sharing all is inherent in Jesus's words and deeds. Everyone who was given to accept those words and deeds was welcome to join Jesus's followers.