The antiterrorism court in eastern city of Lahore also fined Hafiz Saeed 30,000-rupee ($194) on February 12.
Co-defendant Malik Zafar Iqbal, one of Saeed’s close aides, was given similar punishment.
Saeed’s lawyer, Imran Gill, told AFP that he was found guilty of “being part of a banned terrorist outfit” and for “having illegal property.”
Alice Wells, the top U.S. diplomat for South Asia, welcomed the development, writing on Twitter that the conviction “of Hafiz Saeed and his associate is an important step forward.”
She said the move would help keep Saeed’s Lashkar-e-Taiba (LeT) militant group “accountable for its crimes, and for Pakistan in meeting its international commitments to combat terrorist financing.”
Saeed was arrested in July last year and charged with collecting funds for a banned organization. He pleaded not guilty.
U.S. President Donald Trump hailed Saeed’s arrest at the time — writing on Twitter: “After a ten-year search, the so-called ‘mastermind’ of the Mumbai Terror attacks has been arrested in Pakistan. Great pressure has been exerted over the last two years to find him!”
Saeed is the founder of LeT, the militant group blamed by the United States and India for the Mumbai siege in which 160 people, including Americans, were killed.
Saeed has denied involvement in the Mumbai, but India has repeatedly called for his prosecution.
His jailing comes as Pakistan faces potential blacklisting by a world financial watchdog — the Financial Action Task Force (FATF) — for failing to curb terror financing.
Pakistani officials say they are working to meet the Paris-based FATF’s demands ahead of the organization’s plenary meeting on February 16.
Washington has long pressured Pakistan to try Saeed, who is designated a terrorist by the United States and the United Nations.
The United States offered a reward of $10 million for information leading to the conviction of Saeed, who has been repeatedly detained and released over the past 10 years.