My Grandfather was Loren G Disney or L.G. as he was called. No middle name just an initial.
He told my father (or his Mother did) that the initial "G" did not stand for any name. He just decided that Loren Disney was too short, and added the letter "G" himself to complete his name.
He was adopted. L.G.'s parents were married 5 years when they adopted him, then suddenly they had 5-6 children of their own.
For someone who did not complete high school and had trouble reading and writing, he did well for himself. If you read the bit of history about him you will find that he became a constable in a small town in Oklahoma where he met my grandmother.
I discovered that he was also a Rough Rider with Teddy
Roosevelt at San Juan Hill.
Here is a newspaper article citing this.