Brown committed "to combat criminal gangs, human traffickers and illegal firearm and drug smugglers -- within the state, along the coast and at the U.S.-Mexico border," his office said in a statement late Wednesday.
About 55 California National Guard troops are already at the border performing anti-drug enforcement, officials said.
Brown emphasized in his order that the deployment is not a response to President Donald Trump's call to Southwest states to secure the border as part of his administration's immigration crackdown.
"Service members shall not engage in any direct law enforcement role nor enforce immigration laws, arrest people for immigration law violations, guard people taken into custody for alleged immigration violations, or support immigration law enforcement activities," Brown said. "California National Guard service members shall not participate in the construction of any new border barrier."
The troops were sent after California secured federal funding this week, the governor's office noted. The troops are expected to deploy before the end of April and will remain there until at least Sept. 30.
Amid tensions with the president, especially considering California's status as a "sanctuary city," Brown defended his immigration stance earlier this week at a National Press Club meeting.
"Trying to stop drug smuggling, human trafficking and guns going to Mexico to the cartels, that sounds to me like fighting crime," Brown said. "Trying to catch some desperate mothers and children or unaccompanied minors coming from Central America, that sounds like something else."
The governor's move to activate the troops came one day after he was criticized in a tweet from Trump on the issue.
"There is a Revolution going on in California. Soooo many Sanctuary areas want OUT of this ridiculous, crime infested & breeding concept," Trump's tweet said. "Jerry Brown is trying to back out of the National Guard at the Border, but the people of the State are not happy. Want Security & Safety NOW!"
"If you look at what's happening in California with sanctuary cities -- people are really going the opposite way. They don't want sanctuary cities. There's a little bit of a revolution going on in California," he added Thursday during a visit to Key West, Fla.
Earlier this month, Trump ordered as many as 4,000 National Guard troops to the border to assist Border Patrol agents with security and stemming a "surge of illegal activity."
Texas, Arizona and New Mexico have already agreed to deploy about 2,000 troops to the border to comply with Trump's directive.