The panel, which has been meeting for months, cleared officer Juventino Castro in the death of 26-year-old Jordan Baker.
The inquiry marked one of Harris County's first grand jury deliberations in a police shooting following recent unrest over the lack of indictments in the officer-involved deaths of Michael Brown in Ferguson, Mo., and Eric Garner in New York.
Baker's death has gained national attention as another unarmed black man killed by police, a trend that has sparked protests and calls for body cameras on officers.
Janet Baker, who spent most of Tuesday and Thursday last week awaiting a decision at the Harris County Criminal Justice Center, had maintained that Castro profiled her son - who was wearing a black hoodie - as a criminal. Along with activists, she has been accompanied by mothers whose sons have been injured or killed in local shootings.
The grieving mother and her supporters had remained hopeful that the grand jury would indict the officer so that his actions can be considered by a trial jury.
The shooting happened in the 5700 block of West Little York near Antoine, where Baker encountered Castro.
The officer, who was in uniform and had been on the force for 10 years, was working an extra security job at the location because the strip mall's businesses had experienced a recent string of robberies, according to the Houston Police Department.
Castro's attempt to stop Baker in the parking lot led to a brief struggle and foot chase, an HPD news release said. When Baker stopped running away, he reached into his waistband and charged the officer, police contend. Castro fired his gun once and struck Baker. The officer was not injured in the incident, police said.
Castro was placed on standard three-day administrative duty immediately following the shooting. An internal investigation to determine if the officer violated any agency policies or procedures was set to begin after the grand jury delivered its decision, HPD Chief Charles McClelland confirmed last week.
Harris County grand juries have cleared HPD officers of criminal wrongdoing in all shootings since 2008. More than a quarter of the 121 civilians shot by the department's officials from 2008 to 2012 were - like Baker - unarmed, according to a Houston Chronicle analysis.