Answer by taking a quote from the following article:

Edward Rickenbacker was born in Columbus, Ohio, to Swiss German-speaking immigrants. From childhood, he loved machines and experimented with them, encouraged by his father's words: "A machine has to have a purpose". In what was to become one of the defining characteristics of Rickenbacker's life, he nearly died many times in events ranging from an early run-in with a horse-drawn carriage, to a botched tonsillectomy, to airplane crashes. His first life-threatening experience occurred when he was in the "Horsehead Gang".

Rickenbacker wanted to join the Allied troops in World War I, but the U.S. had not yet entered the war. He had several chance encounters with aviators, including a fortuitous incident in which he repaired a stranded aircraft for Townsend F. Dodd, a man who later became General John J. Pershing's aviation officer and an important contact in Rickenbacker's attempt to join air combat.  During World War I, with its anti-German atmosphere, he -- like many other German Americans -- changed his surname; the "h" in "Rickenbacher" became a "k" in an effort to "take the Hun out of his name." As he was already well known at the time, the change received wide publicity. "From then on", as he wrote in his autobiography, "most Rickenbachers were practically forced to spell their name in the way I had..."  He believed his given name "looked a little plain." He signed his name 26 times, with a different middle initial each time. After settling upon "V", he selected "Vernon" as a middle name.  In 1916, Rickenbacker traveled to London, with the aim of developing an English car for American races. Because of an erroneous press story and Rickenbacker's known Swiss heritage, he was suspected of being a spy. En route and in England, agents closely monitored his actions.  On a sea voyage back to America, he came up with the idea to recruit his race car driver friends as fighter pilots, on the theory that such men were accustomed to tight spaces and high speeds. His suggestion was ignored by the military.

did he have a job before he decided to come to the US?
He had several chance encounters with aviators, including a fortuitous incident in which he repaired a stranded aircraft