The latest measure is a slight uptick from the 68 percent who supported labor unions when the survey giant polled the question last year.
Gallup has tracked union approval for decades, and support has gradually increased since 2009.
Support fell below 50 percent for the only time in 2009, but ever since has been improving to levels now not seen in more than a half-century.
The increased support comes as workers at many major companies have pursued union campaigns.
A Starbucks store in Buffalo, N.Y., became the company’s first U.S. location to unionize in December, and more than 200 stores have since successfully held votes to join the union. Starbucks has battled many of those unionization efforts in court.
In April, workers at one of Amazon’s New York City facilities voted to become the first of the e-commerce giant’s U.S. locations to unionize.
Additionally, the first U.S. Chipotle store voted to unionize last Thursday in Lansing, Mich.
The new poll found that 6 percent of U.S. adults report that they are a union member, and 16 percent live in a household in which at least one resident is part of a union.
The results remain in line with Gallup’s range of between 14 percent and 21 percent of adults since 2001 who have said they live in a household with at least one union member.
President Biden has pledged to be the most pro-union president in history. He has hosted union leaders organizing at major companies and spoke at AFL-CIO’s convention in June.
“We’re seeing a resurgence of worker organizations and unionization,” Biden said earlier this month. “Where I come from, that’s a good thing, and it’s long overdue.”
The Gallup poll was conducted between Aug. 1 and 23 through a random phone sample of 1,006 U.S. adults. The sample is weighted to match national demographics, and the margin of error is 4 percentage points.