After spending a few years in New York City, Lamantia established a professional practice in New Orleans. By 1955 he was a partner in the firm Burk, Le Breton and Lamantia, which was noted for its church and school buildings. In 1958, he worked with Arthur Q. Davis to design showrooms for the Orleans Gallery, a cooperative artists' organization of which Lamantia was a founding member. He directed the renovation of of the Presbytere Building and contributed to the renovation of New York's Central Park.
A prolific artist and designer, Lamantia exhibited oil paintings in the Whitney Museum of Art's "Fulbright Painters" show in 1958. He designed room schemes and furnishings for Interiors magazine, and collaborated with Louisiana-based sculptor Lin Emery on a brass fountain for Edgar A.G. Bright. His most recent works were collages, assemblages from his Hurricane Katrina-ravaged collection of Piranesi prints.
James Lamantia was an early and lifelong supporter of Tulane University Libraries' Southeastern Architectural Archive. His donations included his own drawings, Frank Lotz Miller negatives and photographs, Piranesi prints, and countless rare books, including a first edition of John Ruskin's The Seven Lamps of Architecture and Eugène Emmanuel Viollet-le-Duc's Habitations Modernes.
Top: Graduation Photograph, James Rogers Lamantia, Jr. Tulane University Class of 1943. Courtesy University Archives, Special Collections Division, Tulane University Libraries.
Bottom: Robert Helmer (1922-1990). St. Catherine's of Siena Church Baptismal, Metairie. Serigraph. James Lamantia Collection, Southeastern Architectural Archive, Special Collections Division, Tulane University Libraries.