Roosevelt S. Williams, 34 of Lincoln, was arrested following the crash on Sunday evening.
According to Delaware State Police, the horse's rider, 40-year-old Michele Rose, was trying to cross Chaplains Chapel Road in Bridgeville with her horse, "Chance," when she heard a "fast-approaching" motorcycle.
Williams hit the brakes, police say, but still hit the horse on the right side.
Both Rose and "Chance" escaped without serious harm, but Williams appeared to be injured.
A mug shot released by police showed him with wounds to his head.
However, police say, Williams not only refused treatment but got back on his motorcycle and drove away.
Police issued a description of the bike and the rider, and a Georgetown police officer tried to stop him but he allegedly sped off.
Police and troopers began to chase Williams, who was allegedly driving at speeds in excess of 100 mph, and a helicopter was called in to track him.
Finally, police caught Williams when he allegedly slowed near Benson and Jefferson roads.
Police converged on the area and struggled with Williams until he was eventually taken into custody.
Williams was found with synthetic marijuana on him, police say, and he was charged with more than 70 traffic violations.
He was being held on $13,950 cash bond.