His Royal Highness The Prince Augustus Frederick, KG, Duke of Sussex, Earl of Inverness, and Baron Arklow was born at Buckingham Palace. He was tutored at home before being sent to the University of Göttingen in Germany in summer 1786, along with his brothers Prince Ernest and Prince Adolphus. Prince Augustus, who suffered from asthma, did not join his brothers in receiving military training in Hanover. He briefly considered becoming a cleric in the Church of England. While travelling in Italy, he met Lady Augusta Murray (c. 1762-1830), the second daughter of 4th Earl of Dunmore. The couple married in Rome on 4 April 1793, and again at St. George's, Hanover Square, London on 5 December 1793, without the knowledge or the consent of the King. They had two children:
The Duke of Sussex married a second time on 2 May 1831 (again in contravention of the Royal Mariages Act) to Lady Cecilia Letitia Buggin (1793-1873), the eldest daughter of Arthur Gore, 2nd Earl of Arran and Elizabeth Underwood and the widow of Sir George Buggin. On the same day, Lady Cecilia assumed by Royal Licence the surname Underwood. She was never titled or recognized as the Duchess of Sussex. However, she was created Duchess of Inverness in her own right in 1840.
King William IV appointed his younger brother Chief Ranger and Keeper of St. James and Hyde Parks on 29 January 1831. The Duke of Sussex was elected president of the Society of Arts in 1816 and held that post for the rest of his life. He also held the honorary posts of Captain-General and Colonel of the Hon. Artillery Company from 1817 onward.
The Duke of Sussex was the favorite uncle of Queen Victoria. He gave her away at her wedding to Prince Albert of Saxe-Coburg-Gotha. The Duke of Sussex died at Kensington Palace was buried at Kensal Green Cemetery. The Duchess of Inverness continued to reside at Kensington Palace until her death in 1873. She was buried next to her second husband.