What was Elvis Presley's middle name? 

When Elvis Presley was born, his parents named him "Elvis Aron Presley". They named him "Elvis Aron Presley", because it was similar sounding to his stillborn twin brother's name "Jessie Garon". Later in his life, Elvis Presley officially changed his middle name to "Aaron" to become "Elvis Aaron Presley".

Please refer to the following article on elvis.com which explains "Elvis' middle name, is it Aron or Aaron?"