Former Dallas Police Chief David Brown delivered a commencement speech for University of Texas students Saturday evening.

Students selected Brown to be the commencement speaker.

Brown entered national spotlight following the deadly shooting of five Dallas PD officers in July 2016.

Brown is actually a former UT student, although he did not graduate.

"I explained to President Fenves, I said, 'Are you sure they mean Chief Brown?' Because I didn't know if they knew that I was alumni here and as a senior, I decided to leave school and become a police officer," he explained.

Brown said he left the university to join the Dallas police force and fight the "crack-cocaine epidemic" in his old Dallas neighborhood.

"These students really surprised me. It's humbling, awfully humbling, to be here to talk with the class," Brown said.

Brown's speech focused on motivating students to get involved rather than just be onlookers.

"Some of the people who criticize and divide the most, need to be served the most," he told graduates. "Congrats 2017 graduation class of the University of Texas at Austin. Cheers, raise 'em high. What starts here changes the world. Hook 'em horns and I will see you at dinner."

Since his retirement, Brown has worked as a contributor on ABC News. He also wrote a memoir, 'Called to Rise,' which will be released on June 6.