Fargus was intended for his father's business, but at the age of 13 joined the school ship Conway in the Mersey, lent by the Admiralty for training future merchant navy officers. In deference to his father's wishes, however, he gave up the idea of becoming a seaman. He returned to Bristol, where he was articled to a firm of accountants until his father's death in 1868, when he took over the family auctioneering business. He married Amy Spark, daughter of a Bristol alderman, on 26 August 1871. They had three sons and a daughter. One son, Archibald, was a first-classcricketer, scholar and clergyman.
While a clerk Fargus had written the words for various songs, adopting the pen name Hugh Conway in memory of his training-ship days. James Williams Arrowsmith, the Bristol printer and publisher, took an interest in his work, and Fargus's first short story appeared in Arrowsmith's Miscellany. In 1883 Fargus published through J. W. Arrowsmith his first novella, Called Back, an early thriller of which over 350,000 copies were sold within four years. One admirer was the American poet Emily Dickinson. A stage version of the book was produced in London in 1884, and in that year Fargus published another story, Dark Days.
Ordered to the Riviera for his health, Fargus caught typhoid fever and died in Monte Carlo. He was buried in Nice. Several other books by him appeared posthumously, notably A Family Affair, which was serialized in the English Illustrated Magazine in 1884–85 and first published in volume form in 1885.