His Wikipedia entry is here, but it's brief. A much more comprehensive survey of his career can be found here.
Soglow received some of his art training from John Sloan who, among other things, was involved in leftist politics, and helped Soglow get some cartoons published in The Liberator. Soglow also contributed work to The New Masses.
Around the same time he was contributing to The New Masses, Soglow began having cartoons published in The New Yorker, a brand-new magazine intended for sophisticates in that city and elsewhere. Also at this time his style was evolving from the Sloan-Masses-Ashcan style to highly simplified Moderne. His Little King retained that style over its 45-year overall existence.
It was an interesting transformation Soglow made -- from socialist content to taking William Randolph Hearst's shilling and drawing a royal cartoon character.