John LaPlante, a longtime city employee who served as the first commissioner of the Chicago Department of Transportation, died Saturday at 80 after testing positive for the novel coronavirus less than two weeks earlier.

The son of a Cook County judge and the head librarian for the Chicago Public Schools, Mr. LaPlante was a “municipally minded” Roseland native who cared deeply about his city and its government, according to his daughter Leslie.

Mr. LaPlante fell ill shortly after returning from a recent trip to Egypt and Jordan with his wife Linda, who didn’t contract the virus.

“The thought is that that’s where he picked it up,” according to his daughter, who said he tested positive for COVID-19 on March 10.

As Mr. LaPlante fought for his life at Evanston Hospital, tight regulations largely kept his wife and daughter from his bedside. Leslie was finally able to see her father after he was removed from a ventilator Saturday afternoon.

“My mom and I were both able to get protective gear and be with him when he passed away,” said Leslie. “Other than that we weren’t allowed to visit him because he was in isolation.”

It was “bizarre” to watch her father’s health deteriorate as the number of coronavirus cases in the United States rose dramatically.

“I feel like our personal experience actually somewhat reflects how the rest of the people in our country have gradually come to terms with the seriousness of this,” said Leslie.

After graduating from Fenger High School, LaPlante earned degrees from the Illinois Institute of Technology and Northwestern University before enlisting in the U.S. Air Force. When he was discharged as a second lieutenant, LaPlante began working as a traffic engineer for the city in 1965.

During his decades of city work, Mr. LaPlante notably helped straighten Lake Shore Drive’s treacherous “Z-Curve” and was a staunch advocate of bicycle lanes. He also served for years as a 40th Ward precinct captain.

Shortly after rising to become the acting commissioner of the Department of Public Works, Mr. LaPlante retained that title when Mayor Richard M. Daley restructured the department into the CDOT in 1992.

As acting transportation commissioner, Mr. LaPlante was blamed for the Chicago Flood of 1992 after he failed to repair a damaged tunnel underneath the Chicago River that wound up flooding the Loop, costing roughly $2 billion in losses. Though he was forced to resign, many questioned whether LaPlante was unduly scapegoated for the catastrophe.

Following his resignation from CDOT, Mr. LaPlante went to work for nearly three decades as the director of traffic engineering at T.Y. Lin International, a San Francisco-based infrastructure services firm.

“When he finally retired, nobody could believe how old he was,” Leslie said jokingly.

Transportation Commissioner Gia Biagi said members of the department were saddened to learn of Mr. LaPlante’s death Sunday. Biagi credited her predecessor for championing bicycle and pedestrian safety, as well as complete streets design, an approach that seeks to make roadways accessible for travelers using all modes of transportation.

Mayor Lori Lightfoot noted that Mr. LaPlante’s death “reminds us all of a turning point in the transportation life of our city.”

“He was a passionate public servant who helped bring CDOT to life nearly three decades ago,” Lightfoot said Sunday. “In the next phase of his career, he worked to extend Chicago’s transportation legacy into the 21st century. . . His impact in moving Chicago forward can be seen in the streets, sidewalks, alleys and bike paths that line every corner of our city.”

Besde his wife and daughter, Mr. LaPlante is survived by two grandhchildren, Elias and Sara.