To understand what started gambling on sports one has to first examine the historical past of sports gambling in America. The US had a long history of allowing some kinds of legal gambling and even illegal betting to a certain degree. Political control and scandals concerning gaming interests have ended in certain backlashes which have resulted in prohibition or regulation of sports gambling. Standards and laws pertaining to sports gambling have kept changing.

Nelson Rose explains these changes in law as three waves. The 1st wave was during the colonial era that lasted up until the mid 1800s, the second wave started at the end of the Civil War and lasted up until the early Twentieth century and also the third wave commenced while in the Great Depression and is still continuing.

During the Colonial Era, different attitudes were enforced towards gambling. Puritan attitudes were adopted towards gambling and possessing dice, cards, gaming tables etc were banned. Later on it was allowed so long as it was not a calling or trade except for moderate and innocent recreation. Settlers brought with them views that said gambling was merely a harmless activity. The frontier spirit encouraged the appeal of gambling since it involved high risk, high expectations and opportunism.

Eventually all colonies used lotteries as a solution out of economic problems as well as help the colonies. It became a civic responsibility and proceeds were utilized to establish some of the first prestigious universities, build churches and also libraries. Lotteries remained popular right to the early Nineteenth century. Horse racing was also preferred and the Long Island built the very first race track in 1665. Casino gaming started to emerge slowly as roadhouses and taverns started to allow card games and dice.

The Lower Mississippi Valley became an organized and legitimate gambling area in 1800s. The grand river featuring its riverboats was a major trade avenue for both wealthy merchants and farmers. New Orleans soon gained recognition as the gambling capital. During the 1830s southern settlers turned against professional gamblers who were held responsible for committing crimes, debasing morals of society and endangering streets. During 1800s there seemed to be increasing attack of gambling especially lotteries and when operators absconded with the proceeds lottery scandals eventually led to prohibition of gambling.

The Gold Rush in California set off a huge increase in the types of gambling and San Francisco was crowned the new gambling capital in the US. During 1849 and 1855 gambling spread widely and by 1850 California and lots of cities had licensed gambling centers. But soon the Legislature made most types of gambling illegal and a number of professional gamblers were lynched. This prohibition drove gambling activities underground and did not eliminate it. Gambling was legal during 1869-1910 in Nevada.

It is possible to now understand what started gambling on sports in the US. With the numerous scandals within the lottery gambling segments, 35 states in America including California prohibited lotteries. In 1933 pari-mutuel betting was legalized and new automated systems and laws made horse racing betting more honest. In 1978 casino gambling was legalized by New Jersey and Atlantic City was a popular tourist destination. Despite its illegality sports gambling became quite popular and today is a billion dollar industry.