The son of John Hogg, a country gentleman of Durham, he was educated at Durham School, and University College, Oxford, where he made the acquaintance of Percy Bysshe Shelley, whose lifelong friend and biographer he became. Associated with Shelley in the famous pamphlet, The Necessity of Atheism, he shared in the expulsion from the University which it entailed, and embarked on a legal career, being called to the Bar in 1817. Shelley, who did not believe in monogamy, tried to get Mary Shelley sexually involved with Hogg, but she refused.
Hogg's 1832 contribution to Bulwer Lytton's New Monthly Magazine his Reminiscences of Shelley, was highly regarded. As a result, he was commissioned to write a biography of the poet, of which he completed two volumes, but in such a way that the material with which he had been entrusted was withdrawn. This work is probably unique in the annals of biography. It gives a vivid and credible picture of Shelley, but shows no true appreciation of him as a poet, and reflects with at least equal prominence the humorously eccentric personality of the author, which makes it unusually entertaining. Other works by Hogg were Memoirs of Prince Alexy Haimatoff, and a book of travels, Two Hundred and Nine Days (1827). He married the widow of Edward Ellerker Williams, Shelley's friend, who was drowned along with him.
http://www.english.upenn.edu/Projects/knarf/People/hoggtj.html