Abdulazeez Dauda, popularly known as Abdul Inyass, was convicted after a trial held in secret to avoid protests.
Five of his followers were also sentenced to death last year.
These are the first death sentences for blasphemy handed down by a Nigerian Sharia court; those delivered for other offences have not been carried out.
Mr Inyass is a preacher at a local faction of the Tijaniya sect, founded in Senegal by Sheikh Ibrahim Niasse, which has a large following across West Africa.
He was reported to have said that “Niasse was bigger than Prophet Muhammad” during a lecture at an event in May, leading to violent protests in the city.
The BBC’s Yusuf Ibrahim Yakasai in Kano says he then fled to the capital, Abuja, and nine of his followers were arrested for their alleged part in organising the event.
When they were arraigned in court, there were further clashes and the courthouse was set on fire, he says.
Four of the followers were acquitted and the five sentenced to death are appealing against their conviction at a federal appeal court.
Kano has a predominately Muslim population and Islamic courts operate alongside secular courts.
Mr Inyass, whose five-month trial was held in secret for security reasons, will also be able to appeal against the verdict at a federal court.
Several states in northern Nigeria introduced Sharia after the country returned to civilian rule in 1999.
Tijaniya at a glance
The Sufi sect of Tijaniya was founded in Algeria in 1784 by Ahmad ibn Muhammad al-Tijani.
It spread all over the world, with large following in North and West Africa. It also has followers in South Africa, Indonesia and other parts of the world.
There are other Sufi sects in Islam but Tijaniya is the largest.
They have three main daily practices: Asking the forgiveness of God; sending prayers to the Prophet Muhammad and affirming the Oneness of Allah.
Senegalese-born Sheikh Ibrahim Niasse was credited with reviving the sect in the 20th Century. People travel from across the continent to visit his shrine.
They have several factions including the Haqiqa (Realist) group, whose members were convicted of blasphemy in Kano.