The professional wrestler Sam Polinsky decided to go bigly.

After Donald Trump won the presidential election in November, Polinsky, known in the wrestling world as the blonde bad boy Sam Adonis, started carrying a flag featuring the president’s face during matches.

Polinsky, who grew up in Monroeville, wrestles in Mexico’s Consejo Mundial de Lucha Libre, a pro wrestling promotion. His shtick has riled up pro wrestling fans in a country Trump has pledged will pay for a border wall with the U.S.

“His relationship with Mexico is the reason why I’m doing it,” Polinsky, a Gateway High School graduate, said. “It is extra hot.”

Polinsky, 27, played some football and wrestled growing up, but pro wrestling was in his blood. His father attended Bruno Sammartino’s matches at the Civic Arena and entered into the wrestling business as a promoter. His brother, Matthew Polinsky, also known as Corey Graves, is an announcer on “Monday Night Raw,” World Wrestling Entertainment’s flagship TV show.

Sam Polinsky enrolled at the Community College of Allegheny County but dropped out when he received a contract from WWE. After getting sidetracked by a knee injury, he relocated to Liverpool, England, in 2012 before moving to Mexico, one of the sport’s largest markets, last year. He debuted tights featuring Trump in May before adding the flag after this fall’s election.

“People were so taken aback with the picture on my tights, I knew I had to do something with him,” Polinsky said.

Sam Adonis’ partiality for Trump has prompted strong reactions from Mexican fans, who have thrown popcorn or beer — “whatever they can grab that’s not bolted down” — at Polinsky. He also is the target of plenty of trash talk, but fans don’t tend to press their luck against the 6-foot-4, 250-pound wrestler.

Wrestling has often tapped into good-vs.-evil mentality that Polinsky’s character embodies. In wrestling, a good or bad character is known as a face or heel, respectively.

“There’s always been foreign villains in wrestling,” he said. “That’s just pro wrestling 101.”

In the mid-20th century, wrestlers portrayed various enemies of the state, including Nazis, Japanese and Russians, according to Scott Beekman, an associate professor of history at the University of Rio Grande in Ohio, who researches the history of professional wrestling.

“We saw the Russians show up in the 1950s,” Mr. Beekman said. “They show up in the Cold War because Russia is the villain at that point.”

The Iron Sheik was a popular character in the years after Iran’s Islamic Revolution in 1979; the pro-apartheid Colonel DeBeers, who was supposed to be from South Africa, followed in the 1980s and 1990s. Zeb Colter, a former WWE personality, tapped into the spirit of the Tea Party movement.

That us-versus-them approach has waned somewhat in the last two decades, Beekman said, because WWE owner Vince McMahon placed a greater emphasis on wrestling’s anti-heroes — represented by unconventional fan favorites such as Stone Cold Steve Austin.

Polinsky did not vote in the November election but said he supports Mr. Trump. “I’m not the biggest Trump fan,” he said, “but I couldn’t stand Hillary Clinton.” Coincidentally, Trump’s pick for the head of the Small Business Administration is Linda McMahon, the former CEO of WWE.

Polinsky also sees plenty of connections between pro wrestling and politics. In both endeavors, there is plenty of performance art — an ability to remain in character both inside the ring and outside of the arena.

“He’s basically a bad-guy character, and whether you like him or not, he’s not changing,” Polinsky said of the president. “I have a lot of respect for that.”