When Lloyd and Mildred were married in 1923, Lloyd pulled Jack out of Our Gang and enrolled him in military school. Davis first appeared in the first Our Gang short, Young Sherlocks. His final appearance was the 1923 short Derby Day.
After degrees in anthropology and medicine Davis became a successful physician in the Los Angeles area, specialising in cardiology, and associate professor at the University of California, Los Angeles School of Medicine.
He was the grandfather of American actress Carrie Mitchum and actor Bentley Mitchum, and the great-grandfather to Grace Van Dien and Wyatt Mitchum Cardone. Davis died in 1992 in Santa Monica, California of respiratory failure at the age of 78.