When And Why Did Gatsby Change His Name?

In chapter 6 of The Great Gatsby, Nick narrates Gatsby’s personal history and the readers learn that Gatsby isn’t his real name. The real name of Jay Gatsby is Jay Gatz, and he is from a poor family from North Dakota which he does not consider his family at all. The readers learn that Gatsby drops out of St. Olaf after two weeks and how Gatsby meets Dan Cody while working at Lake Superior collecting clams and fishing for salmon. Dan Cody takes Gatsby on board as his assistance and that's when Gatsby falls in love with luxury and wealth.
Dan Cody teaches Jay everything he knows, and it is he who gives Jay a new name and a new lifestyle. By changing his name, Gatsby covers his past shame of a poor upbringing with his common parents and tries to reinvent ‘who’ Jay Gatsby is.
Throughout the book, the readers discover that “Jay Gatsby” is a created identity, made by Gatsby to flee from his past and achieve his American dream. But no matter how hard we try to escape the past, we are always reminded of it and eventually make our way back to it. Gatsby cannot re-create the past, as hard as he tries. He is described as being the most successful character yet even he struggles with the fact that he cannot go back and rewrite the past with him and Daisy in it, no matter how much money he has and how much he spoils her with riches now.