Phillip was born on the 12th of December, 1889, in San Francisco, California, and while not much is known about his early life, it is known that he joined the US Army and he was a Sergeant with the 363rd Infantry, 91st Division when he deployed to Europe in support of World War 1. His actions on the 26th of September, 1918 earned him the Medal of Honor. The citation reads:

After his company had withdrawn for a distance of 200 yards on a line with the units on its flanks, Sgt. Katz learned that one of his comrades had been left wounded in an exposed position at the point from which the withdrawal had taken place. Voluntarily crossing an area swept by heavy machine-gun fire, he advanced to where the wounded soldier lay and carried him to a place of safety.

Phillip received the Medal of Honor on the 22nd of January, 1919 and was the only California native to receive the Medal of Honor during the War and he continued to live in San Francisco. He was never married and was elected to the San Francisco Board of Supervisors in 1923, where he served as Public Administrator for twenty-seven years. He retired in 1953 and loved to travel and fly fish and on the 29th of October, 1987, Phillip Carl Katz died at the age of 97 and was the oldest living Medal of Honor recipient at the time. He is buried in the Cypress Lawn Memorial Park in Colma California: Section C.