In the crazy world of American politics, the label of "Washington insider" is a handicap. Accordingly, Joe Biden's campaign did not focus on his coziness with Washington. So did Americans unwittingly elect the most experienced president in U.S. history?
Yes. Counting years in national office or administration in Washington, It isn't even close. Biden served 44 years as Senator and Vice President (and being VP is perhaps the most relevant experience for the Presidency, apart perhaps from being First Lady). The runner-up is James Buchanan, predecessor to Abraham Lincoln, with 29 years in the House, Senate, and diplomatic posts. Most other presidents had ten years or fewer in Washington.
Back before the prejudice for "outsiders" and against experience took firm hold, John Quincy Adams logged 25 years and James Monroe had 19. In the twentieth century only Gerald Ford and Richard Nixon had substantial experience, with 25 years apiece. But then again Ford was an accidental president and Nixon was the lamentable source of the accident.
Many other twentieth century presidents -- Wilson, Eisenhower, Carter, Reagan, Clinton -- had no national political experience. Of the last seven presidents, only George H. W. Bush and Obama (two years in the Senate) had served in national political office.
Is there another democratic nation in which someone can reach the highest elective office in the land without experience in national politics? Imagine a British Prime Minister who had never served in Parliament. But in the United States, it seems sometimes that even a high-school field trip to Washington might be used against a candidate.
Admittedly the number of years spent in national service is not necessarily a guarantee of success as president. Most of the presidents generally regarded as mediocre had little or no national experience. But Buchanan is one of the perennial candidates for worst president, while his successor Lincoln had only two years in Congress on his resumé. Richard Nixon had vastly more experience than Franklin Roosevelt (seven years as Assistant Secretary of the Navy).
But other things being equal, knowing your way around Washington is not a bad thing. It helps in understanding what is politically feasible and what is not. It helps in knowing where the levers of power are. It helps in identifying the best candidates for high-level appointments. It helps in knowing how to build and sustain public support. In these respects and others, Biden's experience will be an asset to the nation.