Donald Trump's presidential campaign brought this question to mind--have we had presidents with no experience in law, politics, or military leadership? What gave them their popularity in spite of their inexperience, and were they effective leaders?
Reagan came to mind due to his background as an actor, but he did at least serve as a governor before becoming president.
No political experience before being the President? You mean not having held civilian elected office?
Eisenhower's first civilian political office was U.S. President, I think. Though you don't get to be a general officer, much less four or five star general, without being a master politician.
There are plenty of examples of U.S. Presidents having 'limited' political experience--a few terms as governor or in Congress before the Presidency. Shoot, most of our Presidents in my lifetime have had relatively short political careers before becoming President. George H.W. Bush had a longer career as a politician/public employee, but some of that time was serving in appointed (as opposed to elected) positions.
Zachary Taylor was a war general prior to becoming president in 1848 and had no political experience prior to his election, he stated that he had never voted before 1848
Herbert Hoover had been Secretary of Commerce, but had never held elected office before. He had previously been a highly successful business and had led the relief effort after World War I for aid to those left homeless/orphaned/starving after the war (a role he would reprise after the Second World War). Hoover's business acumen and humanitarian credentials went a long way to convincing America to support him.
Other posts here have covered the major Presidents that lacked political experience for the most part. Though Taft had never been elected and was best known as the military governor of the Philippines before he became TR's running mate for his second term (or first full term, however you want to look at it).
As far as businessmen trying to jump straight to the presidency, there are a couple examples of candidates that made it pretty far, though not to the presidency: Wendell Willkie was the Republican nominee in 1940. He was a successful businessman, though with no political experience, and had even supported FDR in 1932. He got over 40% against FDR, but was blown out in the electoral college.
Also, Ross Perot self-financed his independent run in 1992 and created a party apparatus (the Reform Party) to support his run in 1996 (sorry, 20 year rule). While he didn't win any states, he got 20% the first time around and 8% the second.
But also, you have to consider that nomination contests themselves have only been decided through primaries (and some caucuses) for the past not even 50 years. So that is going to limit the historical parallels, since populism isn't generally considered the way to charm men in smoke-filled rooms. Also interesting is that the Republican primary is somewhat MORE democratic than the Democrats', as they (the dems) allow "superdelgates" to hold a significant amount of sway on the convention floor.