Lewis “Ed” Miremont, a Baton Rouge engineer whose firm designed the Catholic Life Center, the LSU Student Union and Our Lady of the Lake Regional Medical Center, among many other local landmarks, died Tuesday at the age of 90.

The cause was a brain injury that stemmed from a fall at his Baton Rouge home, said his son, John Miremont.

Miremont’s firm, Desmond, Miremont and Burks, was a major force of architecture across the city and region for decades, beginning in the 1950s. Among several well-known buildings, the firm built Southeastern University’s master plan, the Tangipahoa and Iberville parish courthouses, the Cortana Mall Regional Shopping Center, St. Thomas More Catholic School and Hammond High School.

The firm even built the East Baton Rouge Parish Prison, as well as a jail in Iberville Parish, said his son, Daniel Miremont.

“They were the powerhouse architectural firm in the state, especially in Baton Rouge,” said Baton Rouge architect Kevin Harris, who added that he attended St. Thomas More Catholic School. The firm’s success, he added, “was this magical combination of political connectedness and talent. … There wasn’t an architect who grew up in Baton Rouge who wasn’t influenced by their work.”

Ed Miremont was born in Little Rock, Arkansas, but grew up in Plaquemine. He had a difficult childhood — as a teenager, he came home from school to find that his 15-year-old sister had died of pneumonia, John Miremont said. His family had lacked the money to send her to a doctor.

Ed Miremont joined the Navy as a teenager during World War II, when he served as a radioman on a fueling ship that earned awards for its service in the Pacific, John Miremont said. He then studied electrical engineering at LSU on the GI Bill, and after graduation went to work for Hays Town, the prominent Baton Rouge architect.

Miremont eventually started his own firm with architect John Desmond that later became Desmond, Miremont and Burks. Desmond, who died in 2008, was known for transferring principles of Acadian architecture to a modern context. Miremont was an engineer, not an architect — he couldn’t draw a straight line, Daniel Miremont said with a laugh. But he helped oversee all aspects of a project’s design, from the firm’s marketing and building concept to its final details.

“He wanted something that would be appealing to the eye, then and now,” John Miremont said. He added: “He was a man who loved his community. He came from nothing, and he wanted to make sure that he left something behind.”

Ed Miremont is survived by Linda Miremont, his wife of 35 years, and five children, all from Baton Rouge.