The cause of death was not immediately clear.
As Toyota president from 1995, Okuda battled a period of poor exports and strong yen by building production bases abroad in a strategy that saw sales surge, while internally championing the development of the revolutionary petrol-electric Prius car.
He was also a rare critic, publicly dismissing a top-job appointment for the founder's grandson as nepotism.
Okuda was born in 1932 in the central prefecture of Mie to a wealthy family that owned a regional stockbroker. He joined Toyota's accounting department in 1955 and, within three years, was overseeing expenses including for executive entertainment.
He told the Nikkei business daily that he confronted people over opaque transactions - superiors and board members alike.
"Within the company, I was shunned and viewed as 'cocky'," the newspaper quoted him as saying in 2013. "However, after a decade of doing this kind of work, I became able to see the company comprehensively from a kind of managerial point of view."
He became Toyota's first leader outside the Toyoda family in nearly three decades, assuming the presidency at a time when shrinking domestic market share added to the headaches of declining Japanese exports and a strong currency.
The next year, in 1996, Okuda spearheaded a strategy dubbed "Vision 2005" to slash engineering costs and reduce export reliance in favour of local production in key markets. In a decade, overseas sales more than doubled, helping global sales soar 67%.
He was also instrumental in bringing the Prius to market in 1997, a year earlier than planned, emphasising the prestige of being the first to perfect mass-produced hybrid vehicles.
Okuda even challenged the power of the founding family - a rarity for a Toyota executive. He became chairman in 1999 and on the eve of Akio Toyoda joining the board a year later, Okuda told the Wall Street Journal that the founder's grandson had to prove he was worthy of leading rather than being handed control.
Toyoda became president in 2009 and chairman in 2023.
"Akio-class talents are rolling around all over Toyota, like so many potatoes," the newspaper quoted Okuda as saying. "The Toyoda family will eventually become a 'shrine' to the company's foundation, to which we will pay respect once a year."
Okuda's chairmanship ended in 2006. He also chaired the powerful Keidanren business lobby from 2002 to 2006 and was president of the Japan Bank for International Cooperation for about a year from 2012.
