Only a handful of New Zealand's 16 polytechnics have achieved that rating.
Pearson began his chairmanship in 2005, after two years as a council member.
The number of students, the suite of programme offerings and student completion rates all increased during his tenure.
EIT recorded 3274 equivalent fulltime students in 2010 and by 2017 that had increased to 4518.
Last year, 138 programmes were offered across the institute's Hawke's Bay, Tairāwhiti and Auckland campuses, ranging from entry-level certificates through to 12 bachelor degrees, five master degrees and 13 postgraduate programmes.
While several polytechnics faced financial difficulties, he points out that EIT has never posted a deficit "a credit to the prudence and conservatism of current and previous governors, management and executive staff".
Among the things he will miss most will be presenting qualification certificates at graduation.
"Steeped in pomp and ceremony, it's a showcase for Hawke's Bay and Tairāwhiti success. Some 30,500 qualifications have been conferred during my term," Pearson said.
"I recall a Māori woman from Flaxmere crossing the stage – she started with an entry-level computing programme at an EIT learning centre and there she was graduating with her Bachelor of Computing Systems.
"It's gold - it makes all the political stuff pale into insignificance, and at the end of the day that's why we are here. It has been a privilege to have been part of that."
EIT chief executive Chris Collins said not only was Pearson probably the longest–serving chair within the tertiary education sector but his tenure would also have to be regarded as one of the most successful.
"EIT has gone from strength to strength under his watch."
Education Minister Chris Hipkins appointed Hastings District councillor Geraldine Travers MNZM as the new chairwoman.
Tertiary Education Commission chief executive Tim Fowler said the commission's role was to help inform Hipkins during the decision-making process.
"The minister considered the appointment at EIT when the term of office of the EIT chair, David Pearson, was due to expire. Mr Pearson had served on the council since 2003 and, while Mr Pearson has made a very substantial contribution to EIT, the length of his service far exceeds the normal standard for good governance of eight to 10 years."
Travers will start on June 1.
"She is a very experienced EIT council member with excellent governance experience. We are confident that Ms Travers will continue to make a valuable contribution to the leadership of EIT."
Fowler added that the Education Minister last year wrote to the chairman to congratulate EIT on a productive year and the solid results delivered.
"EIT has produced operating surpluses since 2010. The TEC does not have any educational or financial performance concerns about EIT."