It’s been said that a bad day at the fair is always better than a good day at work. For Gov. Ron DeSantis of Florida, those two ideas collided on Saturday in Iowa.

Mr. DeSantis, who has been struggling to gain ground on former President Donald J. Trump and is counting on making his mark in the state’s first nominating contest, suffered a series of moments — all beyond his control — that would be enough for any candidate to question his place in the political universe, especially before a near face-to-face encounter with the front-runner at the Iowa State Fair.

Ahead of the Florida governor’s appearance with Gov. Kim Reynolds of Iowa at a “fair-side chat,” a plane flew overhead with a banner that read “Be likable, Ron!” Although it wasn’t immediately clear who was responsible for the stunt, the joke was a reference to advice given to Mr. DeSantis before a 2018 debate during his first run for Florida governor.

Then, during the interview, a small group of liberal protesters with cowbells and whistles sought to interrupt the conversation with Ms. Reynolds, who reminded the crowd to be “Iowa Nice.” Several of the protesters were removed from the event by the Iowa State Patrol. For other candidates, Ms. Reynolds’s interviews have been a safe space with softball questions and few unpredictable moments. Not so for Mr. DeSantis.

But drawing scorn from the left has always been part of the Florida governor’s brand. And Mr. DeSantis’s appearances on Saturday with two of Iowa’s top Republicans — in addition to the interview with Ms. Reynolds, the governor and his family rode the Ferris wheel with Senator Joni Ernst — reflected the attention his campaign is showering on Iowa, where he has pledged to visit all 99 counties.

Mr. DeSantis leaned into his Iowa-centric approach, criticizing Mr. Trump for his attacks on Ms. Reynolds, which the governor called “totally out of bounds” as he spoke briefly with reporters. “She’s never done anything to him,” Mr. DeSantis said of Ms. Reynolds, who is staying neutral in the caucuses. “But that’s just how he operates, to attack one of the best governors in the country.”

Accompanied by his wife, Casey, and three small children, Mr. DeSantis walked through crowds of fairgoers to join Ms. Ernst and Representative Zach Nunn, also a Republican, for a session at the grill flipping burgers and pork chops. Donning a red Iowa Pork Producers Association apron, Mr. DeSantis dove into the retail politics demanded at the busy state fair.

But Mr. Trump, who also visited the fair on Saturday, proved impossible to escape, although the paths of the two candidates never directly intersected.

Mr. DeSantis was trailed for much of the day by Trump supporters with placards trumpeting Mr. Trump as a “back-to-back Iowa champ” in 2016 and 2020. Mr. Trump of course did not win the 2016 Iowa caucuses, placing second to Senator Ted Cruz of Texas. He never conceded defeat.

And while the Trump Team handed out anti-DeSantis fliers before the former president’s speech at the Steer N’ Stein, the trolling was not limited to the fairgrounds, it seems. As Mr. DeSantis finished flipping pork chops, Mr. Trump’s plane appeared overhead, circling the fairgrounds in what Iowa locals say is a nonstandard flight path into Des Moines International Airport, and prompting chants of “We love Trump” from supporters in the crowd.

Mr. DeSantis’s tour through the state fair also exposed him to the kind of unscripted interactions his campaign usually avoids. Some people shouted positive encouragement as he and his family walked by (“We love you, Governor!” “Go get ’em, Ron!”), to which Mr. DeSantis often responded with a smile or a wave.

Others — on both the left and the right — jeered him with cries of “Loser!” “Fascist!” or “DeSanctimonious” (a favored insult of Mr. Trump’s), which Mr. DeSantis ignored. One woman hurled an expletive at him as he carried his young daughter on his shoulders.

All the while, Mr. DeSantis’s family, his wife, Casey, and the children (Madison, 6, Mason, 5, and Mamie, 3), reaped a prize bounty at the fair games, including a milk jug toss and balloon popping. They walked away with at least two oversize Pikachu stuffed animals and what appeared to be a giant koala.

Anjali Huynh contributed reporting.