Decided against earning a livelihood in music and instead pursued a successful career in business, only composing after working hours. he founded a company with a friend in 1907, which eventually became the largest insurance company in the united states and made him a very wealthy man.?

The answer is Charles Ives. He is one of the primary American writers of universal prestige, however, his music was generally disregarded amid his life, and huge numbers of his works went unperformed for a long time. After some time, he came to be viewed as an "American unique". 
He joined the American well known and church-music conventions of his childhood with European workmanship music, and was among the main arrangers to take part in a methodical program of test music, with melodic systems including polytonality, polyrhythm, tone groups, aleatory components, and quarter tones, portending numerous melodic advancements of the twentieth century.