Prescott Bush was a politician. He got his money that same nearly all of them do. From the little people. Us.
Prescott Bush made his money as an investment banker in Connecticut. Only after he was a successful banker did he enter politics. He won a special election in 1952 to finish the term of James McMahon who died in office. He then ran and won re-election to another full term. Afterwards he went back to banking.
Yes, 10 years of his life spent in politics and he was a lifelong politician, wasn't he?