Thomas James Harper was born in Orange County on January 11, 1907.  His mother, Ruth, was a member of the Northcross family, early settlers of Santa Ana and Orange. His grandparents arrived in Orange County from Tennessee in 1877 and the family became prominent as farmers and ranchers. He began his university education at Berkeley, before transferring to Otis and eventually the University of Southern California.  While attending USC, Harper traveled to Europe in the summer of 1929 studying architecture in England, France and Italy. Traditional French and English architectural styles would influence his designs for the rest of his career. 

After graduation, Harper began his first work in Beverly Hills until he came to Laguna Beach in 1929. Family wealth and social connections helped to launch his career while still only being in his 20’s. Despite his young age, Harper began designing, developing and selling real estate.

He went on to be responsible for arranging for the local finances of Santa Ana and Los Angeles institutions. He was in charge of building and designing for Martin C. Delaney, Inc. (Was also a real estate broker for that organization)

His most significant contribution to the architectural history of the city would have to be the Manzanita Cottages. This collection of several small bungalows was built in 1930. That same year he designed his own personal residence on the corner of Catalina and Graceland. The striking home was built of concrete blocks and adorned with a small turret. In May 1936 Harper opened a real estate practice with Al Thompson and Nathan Wilson.
As fears grew that the United States might be drawn into another world war, the nation began draft registration of all men of fighting age. Thomas J. Harper submitted his draft card. On it he is described as 6 foot, 165 pounds, with brown hair and blue eyes. Almost 35 when the war broke out in December 1941, he ultimately was not called to active service.

After the war he went on to be responsible for arranging the local finances of Santa Ana and Los Angeles institutions. He was late employed by the firm of Martin C. Delaney, Inc. as a real estate broker and the head of construction and design.

Thomas J. Harper died on June 9, 1957. He was survived by his wife Marilyn, a daughter also named Marilyn, two sons, Thomas and William, and a stepson, Wesley Tang. He was 50-years old.