On the outskirts of Munich, among gnarled oak trees and sculpted ­angels, stands the grave of Albert Göring. I have made a pilgrimage to bid farewell to this man I never met, yet have grown to know so well. For three years I have retraced his footsteps, visiting his old haunts, trying to put a face to the Göring that history has forgotten. The surname is familiar, thanks to Reichsmarschall Hermann Göring, the notorious Nazi leader and war criminal. Albert, his younger, little-known brother, was his antithesis – a Holocaust hero who devoted himself to saving hundreds of Jews and political dissidents, persecuted by the very regime his brother had helped to forge.

My journey to uncover the extra­ordinary story of the Göring brothers began in 2005. I was standing in the main quad in the University of ­Sydney at my graduation ceremony. My ­parents were trying to operate the camera. My thesis supervisor shook my hand, strangers wished me luck and they all asked: where to now? Would I be ­going on to study for a PhD, or perhaps a career in finance? No. I told them I wanted to find out more about the story that had haunted me since I chanced upon a documentary alleging that Hermann Göring – Nazism ­personified – had an anti-Nazi brother. So, a month after graduation, armed with a round-the-world ticket, I left Sydney. On the face of it, it looked like the proverbial Australian backpacker's adventure. But for me it was a fact-finding mission to cut through the rumour and conjecture that has shrouded the truth of Albert's story and the relationship that developed with his brother. First stop: the US and the ­National Archives in Washington, DC. There I stumbled across Albert's list of the 34 most prominent people he saved during the second world war. These five dog-eared pages would ­become the compass of my journey. With the voices of those rescued by ­Albert whispering the coordinates of my expedition, I headed to Germany.

Hermann and Albert survived an ­aristocratic mess of a childhood, with three siblings. Their father, Heinrich, enjoyed a distinguished diplomatic career as consul to German South-West Africa (Namibia today) and subsequently Haiti. He was often apart from his family and later became a melancholic recluse. His wife, Fanny, became infatuated with a wealthy society physician, ­Dr Hermann von Epenstein. He was at Fanny's side when his namesake, Hermann, was born and upon the birth of her youngest child, Albert Günther, he announced that he would become the Göring children's godfather and house the family in his southern castles.

The family spent most of the year at Burg Veldenstein − an imposing, medieval bastion in Franconia − and summers at Burg Mauterndorf, a fairytale castle in the Tauern mountains of Austria. Meals were announced by a hunting horn, staff were adorned in medieval regalia and an army of minstrels was at their disposal. When Von Epenstein visited the Görings at Burg Veldenstein, he always requested the choicest of the castle's 24 rooms, a short late-night scamper from Fanny's room, fuelling rumours that he and Fanny were having an affair.

"We never had any doubt about it," says Professor Hans Thirring, who enjoyed summers with the Görings. "Everyone who stayed at Mauterndorf accepted the situation, and it did not seem to trouble Hermann or the other Göring children."

It was also thought that Albert was the love child of the affair. "Pate [godfather] had made Hermann his favourite godchild, but after Albert's birth he was always fussing over him," the boys' sister, Olga Rigele, recalls. The rumours intensified as Albert grew up and people began to notice a physical likeness to his half-Jewish godfather. Albert had Epenstein's dark brown eyes and central European ­physiognomy; whereas his brother Hermann was the inheritor of his mother's piercing blue eyes and Aryan features.

Hermann was a rebellious boy. Ill at ease in the confines of the classroom, he bounced from one boarding school to another. At his final one, he cut the strings of every violin and cello in the school band, before absconding. This act had him sent off to military school, where his warrior spirit could flourish. He later distinguished himself as an ace fighter pilot in the first world war.

Albert was said to be a sad boy, preferring a book and the security of the indoors. In school he sat at the back of the class. There seemed to be little other than name to link the two boys. "He was always the antithesis of myself," Hermann told the American psychiatrist Leon Goldensohn, who interviewed him at the Nuremberg war crime trials in 1946. "He was not politically or militarily interested; I was. He was quiet, reclusive; I like crowds and company. He was melancholic and pessimistic, and I am an optimist. But he's not a bad fellow, Albert."

As the brothers began to forge their separate paths in life, their adolescent idiosyncrasies morphed into an ideological chasm. After serving as a communication engineer in the first world war, Albert enrolled in 1919 at the Technical University of Munich to study mechanical engineering. Here he rubbed shoulders with the future leaders of the Third Reich, including Heinrich Himmler, then an agronomy student active in the fraternities, a breeding ground for the budding ­student nationalist movement. Albert appeared to remain politically passive, yet he studied his future foe intently.

Meanwhile, Hermann, the disenfranchised war hero, began to circulate in the Munich beer hall scene, all ears to its rhetoric against the Weimar government and the postwar reparations imposed on Germany by the Treaty of Versailles. In 1922, he was particularly impressed by an orator named Adolf Hitler. An infamous love affair blossomed and, as in classic love stories, a test of devotion was required. It came with the 1923 Beer Hall Putsch − Hitler's first attempt to prise power from the government. Bullet wounds to the groin and hip proved Hermann true, but the coup was quickly quashed and Hermann went on the run.

Four dark years of exile ­followed. Hermann became addicted to ­morphine, lost his grip on sanity and was institutionalised in Sweden. This period also marked the beginning of 12 years of silence between the brothers. Albert shunned Hermann and his political ­ideals. He felt betrayed as a brother and representative of the Göring family. "Oh, I have a brother in Germany who is getting involved with that bastard Hitler," Albert would tell his close friend Albert Benbassat. "And he is going to come to a bad end if he continues that way." Hermann later rationalised: "We never spoke to each other because of ­Albert's attitude toward the party. ­Neither of us was angry at the other. It was a separation due to the situation."

The 1938 Anschluss − when the ­Germans annexed Austria − and looming war would bring an end to the brothers' feud. The two met at Albert's lodge in the peaceful town of Grinzing, north-west of Vienna. Albert was an exhausted mess. Ever since the first swastika appeared in Vienna, he had tirelessly arranged exit visas and funds for his Jewish friends. He came head to head with Nazi thugs in ­Vienna, ­defending elderly Jewish ladies who were mocked and forced to scrub the cobblestone streets on their knees.

In contrast, Hermann brimmed with excitement. He had just arrived in Austria to much fanfare and delivered a chilling speech inciting wholesale ­antisemitism. Buoyed by his political conquest, he granted each of his family a wish. But his mood soured when Albert and his sister Olga pleaded for Hermann to intervene on behalf of Archduke Josef Ferdinand of Austria, the last Habsburg Prince of Tuscany, then detained at Dachau concentration camp. "Hermann was very embarrassed. But the next day the imprisoned Habsburger was free," Albert recollected to his old friend Ernst Neubach.

This element of their relationship puzzled me. The brothers could somehow detach themselves from their public roles when they came together in this private Göring family sanctuary. It was as though their fraternal bond conjured amnesia in Albert, and he could temporarily put aside the ire and grief caused by his brother's regime.

Albert used this arrangement to his benefit and that of others. "He could certainly help people in need himself financially and with his personal influence," says Edda Göring, Hermann's only child. "But, as soon as it was necessary to involve higher ­authority or ­officials, then he had to have the ­support of my father, which he did get."

Albert regularly went to his brother's Berlin office to curry favour on behalf of a Jewish friend or political prisoner, man­ipulating Hermann's ego and playing on his sense of familial duty. In this sense, Hermann was a safety net for Albert. As Albert became ever more ­audacious in his subversiveness, a mountain of Gestapo reports piled up against him. Four arrest warrants were issued in his name during the war and yet he was never convicted. Big brother always came to his aid, however ­politically damaging it might have been.

In 1944, a death warrant hung over ­Albert, demanding his execution on sight. He was on the run, hiding in Prague. Hermann dropped everything to save him. "My brother told me then that it was the last time that he could help me, that his position [had] also been shaken, and that he had to ask Himmler personally to smooth over the entire matter," Albert testified in Nuremberg.

The brothers met for the last time in May 1945, in a transit jail in Augsburg. Hermann was the Allies' prize catch, while Albert was detained for simply being his brother. In the courtyard of the jail, they embraced and Hermann said: "I am very sorry, ­Albert, that it is you who has to suffer so much for me. You will be free soon. Then take my wife and child under your care. Farewell!" Two years later, Hermann was convicted for war crimes and crimes against humanity. He cheated the hangman's noose with a smuggled cyanide capsule.

Albert spent two years in prison, ­unable to convince his interrogators of his innocence. One report reads: "The results of the interrog­ation of Albert Göring, brother of the Reichsmarschall Herman [sic], constitutes as clever a piece of rationalisation and 'white wash' as SAIC [Seventh Army ­Interrogation Center] has ever seen. ­Albert Göring's lack of subtlety is matched only by the bulk of his obese brother." The surname that once enabled Albert to save hundreds of victims of Nazism became the ultimate burden.

Even when Albert was freed in 1947, he could not shake his brother's shadow. No employer would take him on. He refused to take the easy route and ­relinquish the Göring name. He fell into depression, alcoholism and then infidelity. His Czech wife, Mila, requested a divorce and took his only child, Elizabeth, to a live in Peru. He never saw or spoke to his daughter again, nor answered any of her letters.

Now in her late sixties, a successful businesswoman with two talented sons, Elizabeth seems to be resigned to her fatherless childhood. "I was not angry: I was nothing," Elizabeth says. "My mother forced me to write until I was about 10 … But he never answered, you see, he never, never answered! So why should I keep writing to someone who doesn't want me? That was very clear to me – he didn't want me." Yet Albert's wife and daughter still seemed to maintain respect and, ­perhaps, love for him. "One thing I have to say," Elizabeth adds. "I don't know what happened between them and how long it took my mother to decide the ­divorce or whatever, but [my mother and grandmother] never said a word against him." Albert, she says, was the only German her Czech grandmother respected.

Albert died on 20 December 20, 1966, as a penniless pariah, his chest bare of medals and formal accolades. His body was laid to rest in the Göring family plot in Munich. Hermann was given no such honour. As a war criminal, his ashes were tossed into a muddy creek in Munich. Yet, in death, Hermann has continued to hijack the Göring family name; it will forever be smeared with the blood of his ruthless ideology and murderous actions.

As I stand at Albert's grave, it dawns on me that this is as close as I will come to my companion for the past three years. Albert took me into smoky cabaret dens and bohemian cafes. He threw me into the centre of an angry Viennese mob. I was there in Hermann's office as he pleaded the case of a colleague, the Gestapo hot on his heels. Etched on the grave's copper base is the Göring family motto: "Wir sind nicht von denen die da weichen sondern von denen die da glauben" – "We are not among those who yield, but among those who believe." I take one last look and realise it was only Albert who held true to that promise.

Thirty Four, William Hastings Burke's book about Albert Göring, is published by Wolfgeist, £14.99