List of third party performances in United States elections

In the 302 gubernatorial elections since 1990, third party or independent candidates have won at least 5.0% of the vote 49 times (16%), while six candidates have won election (2%). The most recent third party or independent governor to win was Alaska's Bill Walker, a Republican turned independent, in 2014.

Is this statement correct "has a third party ever won an election"?
yes