de Weerdt, who was 75, presided over some of the most famous cases in the history of the NWT, including Roger Warren's murder trial.
He also played a key role in bringing legal aid to the NWT in the early 1970s and penned several rulings on the legality of the 1982 Constitution.
"He was a walking history of the legal system in this territory," said Supreme Court Justice Ted Richard, a former colleague. "He had a ... prolific career."
de Weerdt, who was born in Cologne, Germany, spent most of his childhood in Scotland before emigrating to Canada in 1949 along with his parents, brother Franklin and sister Georgina.
He moved to Yellowknife in 1958, two years after graduating with a law degree from the University of British Columbia. When de Weerdt first arrived in Yellowknife he was one of only two lawyers in the fledgling city and took on the dual role of the crown and the defence.
"His first case was for drinking and driving and I remember him telling me that he was surprised they had cars and roads in Yellowknife at the time," said brother Franklin.
After working for several years in private practice, de Weerdt was named a Juvenile Court Judge in 1971.
He left Yellowknife a few years later to help set up the British Columbia Insurance Corporation, before returning to the NWT in 1981 to sit as a Justice in the Supreme Court.
He held that position until his retirement in 1995.
As news of his death spread, de Weerdt was remembered by friends and colleagues as a passionate jurist.
"The law was his life. There was nothing he would rather do," said brother Franklin. "His idea of a good time was sitting back and reading a book on the law!"
Recently retired territorial Chief Judge Robert Halifax, a former colleague, said de Weerdt had a passionate sense of duty.
"We was thorough, principled and a firm believer that justice should be brought to the people."
de Weerdt leaves behind four children and 11 grandchildren. In lieu of flowers, his family asks that donations be made to the NWT Law Foundation.