The 61-year-old fell from a ladder at his new home in Hamilton, hitting his head on a brick wall in the process.
Mr Edgar retired from the education sector at the end of last year, ending five and a-half years as principal at Tokomairiro High School, and a 33-year career in teaching.
He had welcomed his first granddaughter into the world on December 21 and had moved to Hamilton to be closer to family.
Tokomairiro High School deputy principal Karen Vollweiler described him as an honest man and a fantastic person to work with.
''He was integrity personified - you could trust anything he said.
''He was a man of vision and persistence, and incredibly cautious, so to see him die in an accident like this beggars belief. ... This has shocked everybody. It's completely unfair and unexpected.''
Board of trustees chairman Nathan Tapp said Mr Edgar was a dedicated man, not only to his school and pupils, but to the local community as well.
''He was a member of the Milton Rotary Club - he was always offering a hand with projects in the community.
''If he started something, he really made sure to drive it right through to make sure it worked.
''For staff going back to school to prepare for the year ahead, it's been overwhelming.
''It shows the impact he had on the school.''
Mr Tapp said Mr Edgar's wife Jan was a well-respected relief teacher at Tokomairiro High School, and the board's thoughts were with her and the family.
''It's so very sad to see this happen. It was a very big shock when I heard.
''It was only a couple of weeks ago that we were all wishing him a relaxed and well-deserved retirement.''
Mr Edgar began his teaching career in his home town of Hastings, at Karamu High School in 1980.
Before arriving at Tokomairiro High School, he was deputy principal and acting principal at Otorohanga College.
He had keen interests in cycling and golf, and was also a former marathon runner.
