The tech mogul will issue a letter to 150,000 AGL Energy shareholders on Monday that shows them how to vote for his four board nominees.
AGL is one of the most widely held stocks in Australia and owns the largest portfolio of renewable energy generation and big battery assets of any ASX-listed company - along with its ageing coal-fired plants.
"We believe that the current board is not up to the challenge of delivering on AGL's potential," Mr Cannon-Brookes says in the letter seen by AAP.
AGL's current board includes five directors, and four were set to lead smaller, demerged entities until Mr Cannon-Brookes scuppered the plan.
AGL has rejected three of the four experts nominated for the board by his Grok Ventures investment firm.
Highly respected former energy regulator Kerry Schott, sustainability expert Christine Holman, Tesla's Mark Twidell and experienced board chair John Pollaers are Grok's nominees as self-declared independent candidates.
In its own letter to shareholders, AGL has endorsed Mr Twidell but not the others.
"The board is of the view that appointing all four of the Grok candidates would not add to the overall effectiveness of the board," according to AGL chair Patricia McKenzie.
As an independent director and possible rival chair, Professor Pollaers said he would work to "return AGL to its rightful leadership position".
Mr Cannon-Brookes is also enlisting the support of institutional investors.
"These candidates bring extremely strong operational experience," Geoff Wilson, chair and chief investment officer of Wilson Asset Management, said in the document.
"Their quality and experience gives me confidence that they will represent the best interests of all shareholders."
Snowcap Research co-founder Chris Kinnersley said the board of Australia's largest greenhouse gas emitter "urgently requires fresh ideas and a renewed culture of excellence".
"We believe the shareholder nominees provide the relevant experience critical for navigating a successful turnaround," he said.
Attached to the letter from Mr Cannon-Brookes are instructions on how to vote for the Grok candidates by the November 13 deadline.
The results will be revealed at AGL's annual general meeting in Melbourne two days later.
