Unfortunately, there otherwise seems to be little background material about him on the Internet, if a brief Google search is any guide.
Below are examples of Time cover portrait art, mostly from the 1940s and World War 2.
Probably painted when he was President.
The Italian dictator.
When in command of the Mediterranean theatre for Britain.
The Desert Fox.
For Time's "Man of the Half-Century" cover that appeared around the start of 1950.
Showing Ford Motor Company's gearing up for war production.
Chairman of General Motors. Again having to do with conversion from cars to weapons.
Probably when he was Secretary of State.
Col. Hobby led the Woman's Army Corps during the war.
The comedian. A slightly colorized version of this drawing (or a nearly identical one) was on Time's last 1951 cover.