Mufti Tanveer Alam Farooqi, former president of anti-Shia Ahle Sunnat Wal Jamaat (ASWJ), was sentenced by the court in Rawalpindi that also imposed a fine of Rs 50,000 in addition to the jail term.
Farooqi was nabbed from Trami Chowk here in December with illegal weapons including 12-bore pump action shotgun, two 44-bore rifles, two 9mm pistols and bullets, a police official said.
Initially, police had charged him for violating section 144 which was imposed in the city at that time. But later government intervened and he was charged for possessing weapons and hate speech.
The development comes as part of Pakistan's National Action Plan to counter terrorism after the Taliban attacked a Peshawar school and killed 153 people, mostly children.
However, those found in possession of illegal weapons can be sent to jail for several years.
ASWJ is believed to be supporter of ruling Pakistan Muslim League-Nawaz (PML-N), for which the government is often criticised by opposition. The group is also considered to be the political face of extremist group Lashkar-e-Jhangvi (LeJ), responsible for a number of violent attacks on minority Shias.