Steve Jobs said he wanted to destroy Android and would spend all of Apple's money and his dying breath if that is what it took to do so.
The full extent of his animosity towards Google's mobile operating system is revealed in a forthcoming authorised biography.
Mr Jobs told author Walter Isaacson that he viewed Android's similarity to iOS as "grand theft".
Apple is suing several smartphone makers which use the Android software.
According to extracts of Mr Isaacson's book, obtained by the Associated Press, Mr Jobs said: "I'm going to destroy Android, because it's a stolen product. I'm willing to go thermonuclear war on this."
He is also quoted as saying: "I will spend my last dying breath if I need to, and I will spend every penny of Apple's $40 billion [£25bn] in the bank, to right this wrong."
Apple enjoyed a close relationship with Google prior to the launch of the Android system. Google products, including maps and search formed a key part of the iPhone's ecosystem.
At that time, Google's chief executive, now chairman, Eric Schmidt also sat on the board of Apple.
However, relations began to sour when Google unveiled Android in November 2007, 10 months after the iPhone first appeared.
In subsequent years, Apple rejected a number of Google programs from its App store, forcing the company to create less-integrated web app versions.
Android has subsequently enjoyed rapid adoption and now accounts for around 48% of global smartphone shipments, compared to 19% for Apple.
But its growth has not gone uncontested. Apple has waged an aggressive proxy-war against Android, suing a number of the hardware manufacturers which have adopted it for their tablets and smartphones.
Motorola was one of the first to be targeted, although it is Samsung that has borne the brunt of Mr Jobs' ire.
The South Korean firm is currently banned from selling its Galaxy Tab 10.1 in Australia and Germany because of a combination of patent infringements and "look and feel" similarities. A smartphone ban is also pending in the Netherlands.
Samsung is counter-suing Apple for infringing, it claims, several wireless technology patents which it holds the rights to.
Patents blogger Florian Mueller, who has been following the court cases closely, said Apple would be conscious of its past, where other companies exploited some of its early ideas.
"If Apple doesn't want the iPhone and iPad to be marginalised the way it happened to the Macintosh at the hands of the Wintel duopoly, it has to use the full force of its intellectual property to fend off the commoditization threat that Android represents," he told BBC News.
Mr Mueller - who has previously undertaken consulting work commissioned by Microsoft - was also critical of Eric Schmidt's dual role at the time: "The fact that Eric Schmidt stayed on Apple's board while he was preparing an iOS clone was an inexcusable betrayal of Steve Jobs' trust."
Mr Schmidt resigned from the Apple board in August 2009. He was later quoted by Bloomberg as saying: "I was on the board until I couldn't stay on the board anymore."