No, he’s not the longest serving Governor in history. Not even close.
If he finishes his term he’ll be 10th, just 2 days ahead of Tommy Thompson and just behind Nelson Rockefeller.
http://blog.lib.umn.edu/cspg/smartpolitics/2013/04/the_top_50_longest_serving_gov.php
The longest total service record belongs to current Iowa Governor Terry Branstad (R), he served 4 terms straight (16 years, that’s the most consecutively as well) and is now in his 5th non-consecutive term. Branstad’s record is probably as safe as Joe DiMaggio’s hit streak.
Joe DiMaggio was an Italian-American and played baseball.
Later in life he was featured in many advertisements, including Wachovia Bank and Mr. Coffee.