Presiding Justice A T M Fazle Kabir said the 90-year-old Azam received consecutive sentences for crimes the court broke down into five categories -- incitement, conspiracy, planning, abetting and failure to prevent murder during the country's 1971 fight for independence from Pakistan, BDNews24.com reported.
"Ghulam Azam in effect took part in the killing by giving 'negative signals' to subordinates," Justice Shawkat Hossain said. "That's why he is 'criminally liable' and found guilty."
A defense lawyer called the judgment "unfair" and said Azam would appeal.
Azam was among the founders of anti-Liberation efforts in 1971 who worked with the Pakistani military junta of that time. He is widely considered to have been a member of a group of right-wing backers of the Pakistani Army who strongly support a united Pakistan.
Azam was charged with 61 counts in the five categories, BDNews24.com said.
"Ghulam Azam's case is a unique one. Ghulam Azam was not physically present during these crimes but he has been accused of being the main man and the overseer of the war crimes during 1971," Justice Fazle Kabir said.
The conviction was greeted with anger outside the courthouse, BDNews24.com said.
Shahbagh's Ganajagaran Mancha, which has called for the death penalty for all war criminals, said it rejected the sentencing.
Sector Commanders' Forum said the freedom fighters were "dissatisfied" and urged the prosecution to appeal.