Vikram Singh Bhaduriya, along with his friends, had a heated exchange with the staff of a hotel in Ghantaghar square area when they were not served food in their car, following which he fired from inside the car, DIG Amitabh Yash said.
The injured waiter was taken to a hospital where his condition was stated to be critical, the DIG said.
They fled after the incident, but were later nabbed from Panki area on the outskirts of the city, he said.
Bhaduriya, along with his two associates, has been booked under 307 (attempt to murder) and an illegal country-made pistol was recovered from their possession, DIG said.
BJP MLA Salil Vishnoi said Bhaduriya was expelled from the party two months ago for allegedly supporting the opposition parties.