Brooke was the son of Bertram, Tuan Muda of Sarawak and Gladys Palmer, daughter of Sir Walter Palmer, and heiress to part of the Huntley & Palmers biscuit fortune.
Brooke grew up in England and was educated at Eton College, Trinity College, Cambridge and the School of African and Oriental Studies, University of London. Throughout the 1930s he served the Sarawak civil service in various sectors, including the Land and Registry Department, and as a magistrate.
He enlisted in the British Army as a private soldier in November 1941, during the Second World War, and from 1941 to 1944 served as a Lieutenant in the Intelligence Corps on the staff of the South East Asia Command at Kandy, Ceylon. He was Special Commissioner for Sarawak in the United Kingdom from 1944 to 1945.
Appointed as Heir Apparent with the title of Rajah Muda of Sarawak on 25 August 1937, Brooke was granted the personal style of His Highness. Having been responsible for administering Sarawak between 1939 and 1940, in the absence of the Rajah, he was deprived of his styles and titles on 17 January 1940, then dismissed and expelled from the state in September 1941, following a dispute with his uncle, Rajah Vyner, over his marriage to a commoner, Kathleen Hudden, sister of a Sarawak government official.
In 1944, Brooke was restored as Rajah Muda, after consultations between his uncle and his father. He was, however, deprived of his titles again on 12 October 1945.
In 1946 Rajah Vyner ceded Sarawak to the British Colonial Office, in exchange for a sizeable pension for him and his three daughters. Anthony Brooke, the designated heir, initially opposed the cession to the Crown, along with a majority of the native members of the Council Negri (Parliament). A five-year campaign in Sarawak followed, aimed at revoking the country's new colonial status, in part directed by Brooke from his house in Singapore. In 1948, after the second British Governor of Sarawak, Sir Duncan Stewart, was assassinated by the Malay Sarawakian nationalist Rosli Dhobie, Brooke came under scrunity by MI5, the British intelligence agency, who wanted to "get wind of any other plots he and his associates might be hatching". No evidence was found that he had known of the assassination plot. In 2012, a declassified document from the British National Archive showed that Brooke had had no connection with the assassination of Stewart and that the British Government had known this at the time. This was not revealed at the time as the assassins were found to be agitating for union with newly independent Indonesia and the British Government did not want to provoke Indonesia which had only recently won its war of independence from the Netherlands, and the UK was already dealing with the Malayan Emergency to the north-west.
In 1951, Brooke renounced any claim to the title, although he remained, according to some loyalists, the pretender to the throne.
In 2013, the Acting British High Commissioner to Malaysia attended Brooke's reburial in Sarawak and offered an apology on behalf of Great Britain, clearing Anthony Brooke's name of any involvement.
Brooke was married firstly, in Rangoon, Burma to Kathleen Mary Hudden (1907–1981), daughter of William Edward Cecil Hudden, of Backwell, Somerset, who became the Ranee Muda of Sarawak. They had three children:
1. James Bertram Lionel Brooke (16 August 1940 – 27 May 2017.) was a Life Member of the Sarawak Association, Chairman of the Brooke Heritage Trust, and a Fellow of the Royal Asiatic Society. He married firstly Victoria Holdsworth (born 1949) (she would later marry Sir Paul Getty), married secondly Karen Mary Lappin (born 1955). He had two sons by his second wife and lived in Edinburgh:
2. Angela Carole Brooke (1942 – 1986)
3. Celia Margaret Brooke (3 November 1944 – 17 December 2011), married first to David Ray Harper (grandson of Pir-o-Murshid Hazrat Inayat Khan), married secondly Marcel Captier of Rennes le Chateau. She had a daughter by her first husband:
Anthony Brooke lived for various periods in London, in Sussex, and at Findhorn community in Scotland. In 1982 he married secondly a fellow peace activist: Brigitte (Gita) Keller (born in 1931 in Copenhagen to the Reverend Paul H. Lange), who founded Operation Peace Through Unity (OPTU) in Sweden in 1975. From 1987 until Brooke's death in 2011 they lived together in Wanganui, New Zealand. Brooke was a traveller and lecturer, supporting various movements for peace and universal understanding.
Brooke died at his home in Wanganui on 2 March 2011, at the age of 98. His death coincided with the anniversary of the deaths of two of the four members of the Sarawak Anti-Cession Movement, Rosli Dhoby and Awang Ramli Amit, who were hanged at Kuching Central Prison on 2 March 1950, while the two others, Bujang Suntong and Morshidi Sidek, were hanged on 27 March. The Brooke Heritage Trust stated that Brooke's ashes would be buried, per his last wish, at the Brooke Family Graveyard, near Astana in Sarawak, on 21 September 2013. On that date, in a private ceremony attended by Brooke's wife Gita, his grandson Jason Brooke, British Deputy High Commissioner Ray Kyles, and New Zealand High Commissioner David Pine, Brooke's ashes were buried at Astana.Anthony Brooke, Esq. (10 December 1912 – 24 August 1937)
H.H. The Rajah Muda of Sarawak (25 August 1937 – 16 January 1940)
Anthony Brooke, Esq. (17 January 1940 – November 1941)
Private Anthony Brooke (November 1941 – 16 January 1944)
H.H. The Rajah Muda of Sarawak (17 January 1944 – 1944)
Lieutenant H.H. The Rajah Muda of Sarawak (1944 – 12 October 1945)
Lieutenant Anthony Brooke, titular Rajah Muda of Sarawak (12 October 1945 – 15 September 1965)
Lieutenant Anthony Brooke, titular Rajah of Sarawak (15 September 1965 – 2 March 2011)