Upon graduating from Saint Louis in 1932, Clarence attended night school and studied real estate and insurance. He married Dorothy Sau Pung Tom, with whom he had three children: Lawrence, Wallace and Jocelyn. By the late 1930s, he was managing the family store at Damon Tract, a residential and agricultural area next to what is now known as the Honolulu International Airport. He also began dabbling in real estate.
In 1956, Clarence and his business partner purchased 233 acres of Damon Tract. Less than a year later, the land was rezoned for airport and industrial use. Together, they developed Damon Tract into the Airport Industrial Park.