The jury found Garcia Zarate guilty of possession of a firearm by a felon.
While Garcia Zarate can technically walk out of the courtroom, it's expected he will be taken into custody by Immigration officials and eventually deported back to his native Mexico. Later, U.S. immigration officials said they would deport him.
EXCLUSIVE VIDEO: Man accused in San Francisco Pier 14 shooting admits to shooting
The case gained notoriety because Garcia Zarate is an undocumented immigrant who had been deported several times and had a number of felony convictions.
President Donald Trump reacted by saying there was a "disgraceful verdict."
Trump's tweet came hours after the not guilty verdiict.
Trump said it is "no wonder the people of our Country are so angry with Illegal Immigration."
Steinle's death became part of the immigration debate in this country, with then-candidate Trump criticizing San Francisco for its sanctuary city status during his campaign.
VIDEO: How the killing of Kate Steinle launched a battle over sanctuary cities
The Steinle family has been waiting more than two years for this day. Kate Steinle was shot and killed when she was walking with her father and a friend on the pier.
Garcia Zarate, who was homeless at the time, claimed he found the gun wrapped in a piece of cloth under a swivel chair at the pier. He says he picked it up, and it accidentally fired, hitting Steinle in the back. The bullet, the defense claimed, ricocheted and then traveled 78 feet before striking Steinle.
The prosecution has always maintained that Garcia Zarate had the gun all along, aimed it at Steinle and fired. But, because, he had little experience with guns, the bullet ricocheted first, a common mistake made by amateurs.
TIMELINE: How the Kate Steinle case unfolded
The gun used to shoot Steinle was stolen in San Francisco from the personal vehicle of a federal park ranger four days earlier. The agent works for the Bureau of Land Management, which is being sued by the Steinle family.
A number of witnesses testified in the trial, including police officers and several people who saw Garcia Zarate at the scene, along with several CSI investigators and forensic experts.
The trial began on Oct. 23, 2017.
The jury had a number of choices to make. They could have gone with a second degree verdict, involuntary manslaughter or consider a first degree murder verdict.
Click here to look back at the events of the Kate Steinle murder trial.
The Associated Press contributed to this report.