John Guy "Jack" Pearcey was born in Dagenham, England, on Nov. 5, 1901. He moved with his family to Vancouver, B.C., four years later. Pearcey enrolled at the University of British Columbia's science program in 1919, taking some time away from school to work. During the 1920s, Pearcey worked as a surveyor throughout the province, including around the Britannia Mine in the Howe Sound area. He resumed his studies and graduated with a degree in geological engineering in 1927, starting his career with the American Smelting and Refining Company (ASARCO) that same year.

From 1927 to 1948, Pearcey worked at the Silbak Premier mine in northern British Columbia, where he eventually became a mining superintendent. In 1948 he was transferred to Salt Lake City for four years as Resident Engineer with ASARCO. From 1952 until his retirement in 1966, Pearcey worked at ASARCO's New York office. He then did consulting with a Guggenheim mining company (Straus Exploration Co.) until 1971, when he purchases property in Palm Beach, Florida. He divided his time Between Florida and New York until his death in Palm Beach in 1984 due to a heart attack.

Pearcey was a lifetime member of the B.C. Association of Professional Engineers. He was also an amateur photographer. Pearcey was married and had three children (Joan Cooke, Lynn Allen, and Gail Hall).