He executed 12 prisoners of war and a German missionary and was executed himself after a brief court martial by his British commanders.
Now, 110 years after the war between the British and Dutch Boers in South Africa, the latest attempt by the family and supporters of Harry "Breaker" Morant for a posthumous pardon failed again last week.
Morant, an eccentric British aristocrat who moved to Australia, where he has the same folk hero status as bushranger Ned Kelly, argued he was acting under clear orders from the British commander, Lord Kitchener, to take no prisoners.
But there were no written orders to back his argument and he was executed by firing squad at dawn on February 27, 1902.
Australia's attorney-general, Nicola Roxon, rejected the family's latest appeal to seek a pardon from Britain.
Morant's execution is one of the most controversial cases in Australian military history.
Commander James Unkles, an Australian military lawyer and historian, has been seeking a pardon for Morant and his two co-accused for years.
"The descendants of these men want this case finished this year," he told Australian state radio, the ABC.
"It's 110 years since Morant and [Peter] Handcock were executed and George Witton was sentenced to life imprisonment."
Witton was freed in 1904.
But Australia's attorney-general, Nicola Roxon, disagreeing with her predecessor, said last week that there was no grounds for appeal.
"It would not be appropriate for the Australian government to advocate for a pardon when there is no dispute that Mssrs Morant, Handcock and Witton actually committed the killings of unarmed Boer prisoners and others," Ms Roxon wrote in a letter to Mr Unkles.
"I consider that seeking a pardon for these men could be rightly perceived as 'glossing over' very grave criminal acts."
Mr Unkles and Morant's family argue he was not given enough time to prepare his defence and that there was an unwritten order from Lord Kitchener to execute all prisoners.
Mr Unkles said Ms Roxon or her advisers were afraid of offending the British government and had "made a political decision".
"They don't want to offend the British, and there are powerful institutions and individuals in this country who want to make sure that this case goes no further," he told ABC.
"According to military law at the time, these men were entitled to a full and fair trial, and in particular that they had a right of appeal. The British denied that right of appeal and gave them 18 hours' notice before two of them were executed."
Two years ago, the then Australian attorney-general, Robert McClelland, asked British authorities to re-examine the case.
Morant, whose skill with horses earned him the nickname "The Breaker", has been celebrated in film and song.
A horse-breaker and sometime poet said to have fled England to avoid paying debts, he volunteered to serve with the British Bushveldt Carbineers in the war, the first the newly formed Australia was involved in.
Lord Kitchener was notorious for his scorched-earth policy in Africa.
He also was a senior commander involved in the disastrous First World War Gallipoli campaign in Turkey to seize the Dardanelles strait to allow the Russian navy passage from the Black Sea to the Mediterranean.