Not only does Jay Gatsby create his personage as an Oxford man of great wealth, but he recreates his childhood by not acknowledging his parents, poor farmers, as his own. In fact, he changes his name from Gatz to Gatsby.
While Jay Gatz attends a Lutheran college in southern Minnesota where he must work as a janitor to put himself through school, he mets Dan Cody, who invites him onto his yacht, introducing him to the life of the wealthy. Jay lives with Dan Cody until the man dies. With some wealth of his own and his dreams, Jay, then, enters the army.
Near his army town, Jay meets his femme fatale, Daisy: "She was the first 'nice' girl he had ever known. Knowing that the "invisible cloak of his uniform might slip from his shoulders," he takes advantage of what he can get, including Daisy, whom he deludes into believing that he is of the same socio-economic class as she; he assures her he can support her. As Nick puts it, Gatsby "had committed himself to the following of a grail." Gatsby becomes aware of the power of riches. As a dreamer, Gatsby's obsession becomes what he lives for, his "American Dream."
After completing his tour of duty in the Army, Gatsby attends Oxford and, later, returns to the U.S. where he becomes involved in a drug ring, acquiring great wealth in his criminal activity. After learning that Daisy lives on Long Island, in order to be near her, he purchases a mansion on the other side of the bay. When he discovers that his neighbor Nick is a cousin of Daisy's, he asks Nick to take him to the mansion of Daisy. From this point the present action of the plot takes place.
The truth about Jimmy Gatz's early life isn't revealed until after his death when his father arrives from North Dakota to attend his funeral. The old man shows Nick a battered copy of Hopalong Cassidythat he son had owned as a boy and in which he had written down his daily schedule and a list of General Resolves. Both and schedule and the "resolves" tell much about Gatz in his youth.
According to his schedule, he rose early (6:00 am). Most of his day was spent working; the remainder of his time was scheduled in activities to improve himself. He exercised to build his body and studied to improve his mind. He practiced "elocution, poise and how to attain it" for an hour each day. An hour was spent in studying "needed inventions." Of his entire day, he set aside only thirty minutes for fun: "Baseball and sports."
His general resolves included not wasting time, not smoking or chewing tobacco, and taking a bath "every other day," surely a luxury in a poor farm house. He also resolved to read an "improving" book or magazine each week and to save money. Five dollars was crossed out; three dollars was more realistic to him. In 1906 (the date on the entries), this savings would represent a great deal of money of a young working adolescent. The last resolve on his list indicates something important about his character: "Be better to parents."
When he was young, Jimmy Gatz dreamed of success, of a better life (the American Dream), and he worked hard to fulfill his goals. After he ran away from home as a teenager, he worked as a janitor at St. Olaf's College in order to go to school, but he was too restless and impatient to stay there. His dreams were calling him. Falling in with Dan Cody set him on another path, one that led to a rather glamorous life on Cody's yacht and, eventually, to Daisy Buchanan. Once he met Daisy, she became the Dream. All that the once hard working boy from North Dakota could have become was lost.
Fun question! The young James Gatz is discontented. He is not happy with the family he was born into:
"His parents were shiftless and unsuccessful farm people—his imagination had never really accepted them as his parents at all."
We don't know too much about his boyhood, but as a young adult:
"he had been beating his way along the south shore of Lake Superior as a clam-digger and a salmon-fisher or in any other capacity that brought him food and bed."
Gatz was sort of self-absorbed, attractive, made strong and tan from hard work. "He knew women early..." so he was a bit of a ladies' man, but he didn't seem to have a lot of respect for women:
"since they spoiled him he became contemptuous of them, of young virgins because they were ignorant, of the others because they were hysterical about things which in his overwhelming self-absorbtion he took for granted."
What he was really after couldn't be found in the beds of country girls, no matter how many there were.
"But his heart was in a constant, turbulent riot."
Young James Gatz was constantly striving to be something greater...to transcend his origins and become something great. He longed not only for the life money would bring him but for the status that came with being a part of the upper class. He was not at all comfortable with being poor. He even blew his first chance at college because he was too embarrassed to be the school's janitor to pay his tuition.
In Dan Cody Gatz finds all the things he was looking for. Here was a man of money, power, and prestige. This is the man who becomes Gatz's mentor under the name "Gatzby." Unfortunately, Cody was not the best example of upper class values as Cody himself was "new money" having become rich striking gold. In the end, the newly created Gatsby has been given tutelage by a man who himself only "kind of" know how to act rich. Thus, Gatsby suffers later in life by not quite getting the upper class values down pat (like his annoying habit of referring to people as "old sport."