Outside directors Jenifer Rogers and Keiko Ihara, members of corporate governance committees created in the aftermath of the arrest of former chairman Carlos Ghosn, pushed for Saikawa's departure at a board meeting that went on for several hours at Nissan Motor's Yokohama headquarters, the sources said.
Ihara, a Japanese racing driver, and Rogers, an American lawyer, also lobbied to install Saikawa's right-hand man, Yasuhiro Yamauchi, as interim CEO until a successor was found, the two sources with knowledge of the meeting said.
The intervention suggests that even as the automaker was wrestling with its worst crisis since Ghosn's dramatic fall from grace, it took pressure from company outsiders to oust his former protege.
Nissan said on Monday that Saikawa will resign on Sept. 16, after he admitted to being improperly overpaid by $440,000.
The stand taken by Ihara and Rogers, the only women on Nissan's board, is also a rare example of the influence of foreigners and women in Japanese boardrooms, which was almost unheard of a few decades ago.
Nissan declined to comment.
"To improve Nissan's relationship with its dealers, suppliers and customers, Rogers argued that Saikawa had to leave," said one of the sources, who declined to be identified because the information has not been made public.
Saikawa's departure is just the latest upheaval for a company battered by the Ghosn scandal, a plunge in profit and a strained relationship with France's Renault, its biggest shareholder and automaking alliance partner.
Saikawa, who had worked for Nissan for 42 years, had long pledged to turn the company around before "passing the baton" to the next generation, a phrase he frequently repeated.
STRAINED ALLIANCE
In June, Nissan set up a trio of committees to improve its governance. Rogers, a former Fulbright scholar, joined the audit and compensation committees. Ihara was named chair of the compensation committee and sits on the nominations committee.
Rogers was the first to argue persuasively that Saikawa should step down and other board members then echoed her view, said an alliance source, who was briefed on the meeting.
Another board member, Renault Chairman Jean-Dominique Senard, had not advocated for Saikawa's departure but supported the proposal, the alliance source said.
Renault sources have acknowledged some concern that Saikawa's exit could interrupt talks underway on reforming their strained alliance, prolonging uncertainty over its direction.
Yamauchi, who will take over as temporary chief executive, is expected to stay in that post until October, when a permanent replacement is due to be appointed.
The frontrunners so far include the head of Nissan's China operations and an executive tasked with leading Nissan's revival, Reuters reported earlier.
One board member initially voiced concern that asking for Saikawa's immediate resignation would be rash and that he should stay until a successor was found, one of the two sources said.
In the end, the decision was unanimous, and Saikawa was told he must go, a fourth person familiar with the matter said.
Hours later, he sat in front of a room full of reporters and said he would pass the baton - within a week.
(Additional reporting by Linda Sieg in Tokyo, writing by David Dolan and Naomi Tajitsu; editing by David Clarke)
By Naomi Tajitsu, Maki Shiraki and Laurence Frost
