She was de facto wife of George Johnston, who was for six months acting Governor of New South Wales after leading the Rum Rebellion.

On board the ship, traveling to Australia, she met George Johnston, a first lieutenant in the New South Wales Marine Corps, which had accompanied the First Fleet.

From 1800 she called herself "Julian" instead of Abrahams, after a renowned Judeo-Spanish family, originally Juliano and presumably the name of Rosanna's father.

Rosanna (now named Rosetta Julian)[6] in 1805, aged 18 years, married emancipated convict Isaac Nichols, who was a modest businessman in the colony and who was appointed in 1809, by the military junta, as the first postmaster in New South Wales.

Esther's and Johnston's eldest son, George, had received his first land grant of 500 acres (200 ha) at Bankstown on 23 April 1804 from Governor Philip Gidley King.

On 26 January 1808, Johnston, now a major, led the Rum Rebellion, which overthrew Governor Bligh and acted as Lieutenant-Governor of the colony.

A year after his return to Sydney, on 12 November 1814, Johnston and Esther, married at St John's Church in Parramatta, with Rosanna and her husband, Isaac Nichols, acting as witnesses at the wedding.

Their oldest son, George, who had considerable landholdings in his own right, died from a riding accident on 19 February 1820, unmarried, childless and intestate.

Among their descendants was Rear Admiral Sir David Martin (1933–1990), a senior officer of the Royal Australian Navy and later Governor of New South Wales.

In 2002 a pavilion was dedicated in Bicentennial Park, in Johnston Street, Annandale, New South Wales, near the Anzac Bridge.