Der Spiegel reported John Ehret, whose father was an African-American soldier and mother a native German, took the post Friday in Mauer near Heidelberg in southern Germany, The Local.de said.
Ehret, who did little campaigning, captured just over 58 percent of the vote to defeat a civil servant in the village, which has about 4,000 residents.
The Local.de reported observers said Ehret benefited from an "Obama effect," though he did not seek to compare his candidacy to that of U.S. president Barack Obama.
Ehret's father was stationed as a U.S. soldier in Karlsruhe, Germany, and his mother suffered a brain tumor when Ehret was a toddler. She gave him up to a children's home when he was 2 and he was adopted at 6 by the Ehret family of Mauer.
John Ehret was the village's only black resident His adoptive father was a Social Democratic Party member on the local council.
The new mayor had been the first black employee of the Bundeskriminalamt, the German equivalent of the FBI, and was sent abroad numerous times.
He said he's never experienced discrimination in Germany.