After graduating in 1981 from UC San Diego with a master's degree in critical theory and 19th- and 20th century art history, McManus began writing reviews for Art Week magazine, where he eventually became a contributing editor.
In fall 1987, the Laguna Art Museum hired McManus, by then regarded as a scholar specializing in Southern California art history, as its chief curator. McManus, at the time the third chief curator in less than four years, arrived during a transitional period for the museum and an institutional shift to focusing more closely on California art history, said Bolton Colburn, a former director of the museum.
McManus fit the sea change, well-versed in Southern California art from 1890 to World War I and movements such as the development of California modernism between 1930 and 1950, Colburn said.
The most important exhibition McManus organized was "California Light: 1910 to 1930." The 1990-91 exhibition, which was featured at the Laguna Art Museum as well as the Crocker Art Museum in Sacramento and the Dixie Gallery Gardens in Memphis, took a scholarly approach to differentiating California Impressionism from other American Impressionist movements.
In an essay in an accompanying book, McManus wrote about painting and the nature of California sunlight, based on his discussions with climatologists.
McManus resigned from the museum in 1989. He went on to teach at Cal State Fullerton and then Laguna College of Art and Design until his health began to deteriorate in 2004.
Born Nov. 22, 1952, in Cleveland, McManus was the second of five children in an Irish-Catholic family. He graduated from the Cleveland Institute of Art in 1976.
He traveled to California to attend UC San Diego as a regents fellow in the university's MFA program in critical theory and 19th- and 20th century art history. While at UC San Diego, McManus became aware of what he saw as a gap in scholarship on California art history.
"In New York, Cleveland and other regions of the country, there has been a lot of attention to historic regional artists, but in this area of the country, the scholarship is just starting," McManus told The Times in 1987.
His own artwork, a series of intensely colorful and visually dense cardboard collages, was featured in four exhibitions at the Peter Blake Gallery in Laguna Beach between 1995 and 2004, two of which were solo shows.
He is survived by his third wife, Stephanie, and four siblings.
A celebration of his life is planned for 2 p.m. Sunday at the Laguna College of Art and Design.
Devin Kelly writes for the LA Times. Kelly can be reached at email@example.com.