Which Pennsylvania post commander was also The American Legion's cartoonist?

Abian "Wally" Wallgren. Wallgren was a cartoonist before The American Legion existed - he created several comic strips in national newspapers before World War I. During the war, he served as a sign painter and with the 5th Marines, 1st Division in France. He became beloved among his fellow servicemembers for his satirical cartoons in Stars and Stripes, even bringing him to the notice of Gen. John Pershing.

After the war, Wallgren became a regular cartoonist for The American Legion Weekly (later The American Legion Magazine), the National Legionnaire and more. The attached cartoon is from a November 1921 edition of the Weekly. He also served as commander of Thomas Roberts Reath Marine Post 186, a Philadephia post that became inactive in 2005.

Wallgren continued to contribute cartoons right up until his death in March 1948; the June issue of the magazine featured a short obituary in his allotted space, ending with, "The world is poorer by his passing."