Authorities said 44-year-old Nathan Van Wilkins was taken into custody at a store in Jasper, about an hour north of Tuscaloosa.
"He had confessed to his family, and his sister called us," Jasper Police Captain Larry Cantrell told Reuters. "The minute we walked in, he threw up his hands."
Earlier, Tuscaloosa Police Chief Steven Anderson said the motive was unclear.
Cantrell said Wilkins did not appear to know anyone at the bar.
"He said, 'I wanted to die and I was hoping the Tuscaloosa Police would kill me, but I got scared and left,'" Cantrell quoted Wilkins as saying.
Wilkins is being held in the Tuscaloosa County Jail on one count of attempted murder, and police said they were getting warrants for additional charges including shooting into an occupied building.
Police were investigating whether the shooting at the Copper Top bar in downtown Tuscaloosa w as connected to an earlier shooting at a residence in the nearby town of Northport, Anderson said. One person was injured in that incident.
Most of the 17 people transported to DCH Regional Medical Centre for injuries related to the shooting suffered shrapnel wounds, said hospital spokesman Brad Fisher.
The victims ranged in age from early 20s to mid-30s. The police chief said three of the wounded were students at the University of Alabama, which is in Tuscaloosa.
Five people were admitted to the hospital, and 12 were treated and released as of midday Tuesday (local time), Fisher said.
One man remained in critical condition, one man was in serious condition and three other people were in fair condition.
"...We heard the gun shot and no one really knew what to think. The first gunshot took place, then about 20 seconds later, then that's when he really started firing them off. After that everyone really scattered," Tuscaloosa News quoted Riley Dunn, a University of Alabama senior who was injured in the attack, as saying.
