The O's boss has transformed the fortunes of the club, who now proudly sit at the summit of the National League.
When the 49-year-old took the reigns last year, the club were sitting 20th in the table.
Speaking of his new two-and-a-half year contract, Edinburgh admitted it was a no brainer.
"It was an easy decision for me to sign this extension, there was no second thought," he told the club's website.
"It was just when can we get it done and how long can it be for. I don't think I have been happier for many a year now."
Orient chairman Nigel Travis added, "Justin has demonstrated in the last 13 months what a great leader he is for Leyton Orient Football Club.
"We are absolutely delighted that he has agreed to extend his stay with us and I believe this will have a very positive impact on the Club as a whole."