Farran initially worked in the National Museum and in the Royal Dublin Society's Fishery Survey.
He was born on 21 November 1876 at Templeogue, the son of Edmond Chomley Farran and his wife Anne Hume Ryan; his father, who was independently wealthy, died in 1881.
Most of his work was published in the Scientific Investigations of the Fisheries Branch of the Department of Agriculture and Technical Instruction.
Farran did still manage to continue his work with planktonic organisms throughout the remainder of his life even close to his death on January 5, 1949, at the age of 72.
Farran still studied after his retirement, and even participated in an experiment of breeding of oysters in tanks at Cromane in 1947 and 1948 just before he died.