Norman Rockwell's Which One? (Undecided Voter) achieved $6.5m at Sotheby's American Art sale on November 21.
The piece dates to 1944 and references the tight presidential race between Democratic incumbent Franklin D Roosevelt and his Republican challenger Thomas E Dewey.
Like most of Rockwell's most memorable works, it was used as the cover to an edition of the Saturday Evening Post.
Rockwell's work has become increasingly valuable in recent years; he posted a string of record sales in 2013.
His masterpiece, Saying Grace, made $46m that year.
Liz Sterling, head of Sotheby's American art department, said: "We were particularly delighted… to introduce Norman Rockwell's Which One? to auction for the first time. "
"The election-themed painting now ranks among the top auction prices achieved for the artist."
Gray Day (1935-1937), a work by the modernist painter Rockwell Kent, sold for $852,200 - setting a new record for the artist at auction.
Kent was a keen explorer and transcendentalist who travelled widely in the world's most remote wildernesses.
He spent many years living in Alaska, Tierra del Fuego and Greenland - where he produced this work.
While Kent is perhaps best known for his distinctive woodcut illustrations, which were published widely, his powerful landscape paintings have a strong following.
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