Smith, 24, is expected to surrender on an arrest warrant for the gun charges later this month. If convicted of the felonies, he could face up to four years and four months in custody, prosecutors said.
The 49ers star faces the weapons charges after they were found by Santa Clara County sheriff's deputies in his home in unincorporated San Jose after a June 29, 2012, party that turned violent when gang members showed up and paid a $10 admission fee, prosecutors said.
Deputies recovered two rifles in Smith's bedroom, including an Armalite AR-10(T) rifle, and a subsequent search of the home two weeks later found three other firearms, including two Bushmaster assault rifles, Deputy District Attorney Brian Buckelew said.
None of the five rifles had been registered with the California Department of Justice, prosecutors said.
Deputies also located several large capacity ammunition magazines lying on the floor of Smith's bedroom and a cache of bullets of several different calibers, expended and unexpended, in his bedside table, prosecutors said.
Sheriff's officials submitted the case to the district attorney's office in July and prosecutors began a secondary investigation that determined three of the firearms were illegal assault weapons under California law, Buckelew said.
Smith bought three assault weapons on two separate occasions in Arizona in 2011, including two in Phoenix from a gun dealer on Dec. 10, 2011, a day before the 49ers played the Arizona Cardinals, prosecutors said.
The assault rifles are legal to own in Arizona but cannot be purchased or even possessed in California, according to Buckelew.
According to prosecutors, during a confrontation with guests at the 2012 party, Smith fired his .45-caliber handgun twice from his home's balcony and later fired several more times in the air.
Another guest shot and injured two people and Smith himself was later stabbed, prosecutors said.
Another person went into Smith's bedroom, removed one of his assault weapons and then walked around with it during the party, prosecutors said.
According to court filings in the DUI case, the California Highway Patrol arrested Smith on Sept. 20 for DUI and having a blood-alcohol level above .08 after he failed three field sobriety tests, tested at a .15 blood-alcohol level and had "slow slurred" speech.
A resident on Bentley Ridge Drive reported to the CHP seeing Smith back up the truck, speed and smash into a tree beside the resident's driveway, according to court documents.
The CHP reported that at the accident scene, officers saw tree branches on the hood of Smith's truck, burned rubber on the truck's body and a large amount of rubber tire debris where Smith crashed next to the driveway.
The truck "was stuck in the front yard" and its rear tires "caused damage to the front lawn and the tires became bald," a CHP officer reported.
A CHP officer asked Smith for his license and registration and Smith told him it was in the glove box, which was empty. In the center console, the officer found two white envelopes with one pill each inside, the CHP reported.
One envelope was labeled "Metaxolone," a prescription muscle relaxant, and the other labeled "Indometacin," a prescription pain reliever, according to a report by San Jose police.
San Jose police later reported that Smith's pickup, a 2011 Chevrolet Silverado, had license plates registered to Smith's 2013 Dodge Challenger and that the Silverado's registration was out of Kansas and had expired in 2012.
Smith also had a pipe in the center console of his vehicle that the CHP confiscated, according to the CHP.
The felony illegal weapons and misdemeanor DUI counts were charged today as separate, stand-alone cases, said Buckelew, who is prosecuting the felony case.
Smith's defense lawyer, Josh Bentley, of San Carlos, could not immediately be reached for comment.