Neither pie nor apples originate from North America and the idea of apple pie predates the North American colonies. Apples were initially transported to North American colonies from England as saplings (and prior to that, from Central Asia), spices to make apple pies had to be imported from other tropical English colonies. However the most popular pies in England are savory meat pies, sweet fruit pies became unusually popular in the US. During colonial times most apples were grown for cidermaking instead of eating, but a variety better for eating called Newtown Pippin were bred in America. Thomas Jefferson wrote that "they have no apples here to compare with our Newtown Pippin." The first American cookbook written by Amelia Simmons in 1796 titled American Cookery contained 14 recipes for various apple pies. John Lehndorff of American Pie Council said: "When you say that something is 'as American as apple pie,' what you're really saying is that the item came to this country from elsewhere and was transformed into a distinctly American experience."

The phrase first appeared around 1920's. Oxford Dictionary cited a 1924 Gettysburg Times advertisement for "New Lestz Suits that are as American as apple pie".

It is? As a non American I most certainly do not think of apple pie as something American.