Not yet. Ron Paul (ran for President with the Libertarian Party 1988) has a chance to win the Republican nomination in the 2012 election cycle.
No, there has not been a president who could be identified as "libertarian".
As of 2012, no.
John Hospers ran as the Libertarian Party candidate for President in 1972, but only had ballot recognition in Colorado and Washington.
Bob Barr is the Libertarian Party candidate for President of the United States.
The Libertarian Party
In 2008, the Libertarian Party nominated Bob Barr for President and Wayne Allyn Rootfor Vice President. George D. J. Phillies and Chris Bennett also ran in 2008 as Libertarian Party candidates, but they received only 0.1% as many popular votes as Barr/Root.
Libertarian Party of California was created in 1971.
The Libertarian Party is anti-amnesty.
Libertarian Party of Mississippi was created in 1971.
Libertarian Party of Nevada was created in 1971.
Libertarian Party of Florida was created in 1971.
Libertarian Party of Wyoming was created in 1971.
Libertarian Party of Minnesota was created in 1971.
Libertarian Party of Illinois was created in 1971.