Shakirullah Shakir was riding a motorcycle near Miran Shah, the main town in the North Waziristan tribal area, when he was shot, the officials said.
He was a senior commander and spokesman for the Fidayeen-e-Islam wing of the Pakistani Taleban. He once claimed his group had trained more than 1,000 suicide bombers at camps in North Waziristan.
No group has claimed responsibility for his killing.
Both North Waziristan and South Waziristan are key sanctuaries for the Pakistani Taleban, which has declared war on the Pakistani government.
Elsewhere in the north-west, a senior Pakistani Taleban commander yesterday said he is splitting from the group in protest over attacks against civilians.
Fazal Saeed said he is forming his own militant group, Tehrik-e-Taleban Islami, and will focus on fighting Nato troops in Afghanistan. The Pakistani Taleban - Tehrik-e-Taleban Pakistan - is mainly focused on battling the Pakistani government.
Fazal Saeed, leader of the Pakistani Taleban in the Kurram tribal area near the Afghan border, accused the main group of targeting civilians in suicide attacks and bombings in mosques.
He said: "We have repeatedly protested over killing unarmed and innocent people in these attacks, but no heed was paid, so we are splitting from Tehrik-e-Taleban."
Thousands of civilians have been killed in attacks in Pakistan. The Pakistani Taleban often deny responsibility for attacks that kill large numbers of civilians, but they are widely believed to carry them out.