Frank Clarke was born on the ranch near Laytonville, Mendocino County, California, where he spent most of his life.
He graduated cum laude from UC Berkeley in 1911 and earned his Master's degree in 1912 with a major in Entomology and Parasitology. He was asked to take a position on the faculty as a parasitologist but declined, preferring to return to the ranch.
For a short time Frank accepted employment with the California Fish and Game Commission establishing the skeletal differences between male and female deer. His findings have been used to convict those who have killed and dressed does and claimed the carcasses were those of bucks.
His father and grandfather had experimented with several breeds of sheep in a effort to determine which was best suited to the particular environment of the Clarke Ranch. They had shown that finewools were indicated - Rambouillet and Merino. Frank set out to improve these sheep through the purchase of the best individuals to be had anywhere. Often he paid top prices for Rambouillet stud rams to be used on his range ewes. Coincident with this breeding program he developed a method of preparing the clip of about 1400 fleeces to make it most attractive to wool buyers. The fleece was folded and rolled in such a manner that the most attractive areas were on the outside. The meticulous care given the clip, regardless of prevailing price, and the care that had been exercised in animal selection and feeding soon rewarded the owner. The clip became known among buyers as the best in California, commanding a substantial premium on the market. His fleeces also took championships in Chicago, Denver, Portland, and Texas wool shows. Frank Clarke was one of the earliest participants in the annual wool show sponsored by the California Wool Growers Association and his entries were consistent winners.
Frank was a member of Alpha Zeta and the Society of Sigma Xi honor societies. On his ranch he secured data that made him one of the State's leading authorities on brush clearance, wildlife management, and range improvement. His contributions to the sheep industry were formally recognized by his election to the presidency of the California Wool Growers Association.