Police said Kamal Attoh, 37, was behind the wheel of an SUV when it jumped a curb and struck the group. Prosecutors allege his blood alcohol content was three times the legal limit.
The victims were out walking in the area of Turtle Rock and Ridgeline drives Wednesday night. Jeongmi Choi, 45, was killed. Her husband and two teenage children were severely injured.
As of Friday, the man remains in serious condition and the 15 and 18-year-old are expected to recover.
After plowing into the pedestrians, the SUV continued on down the side of a small hill and stopped just short of an apartment complex.
According to the Irvine Police Department, there was no apparent wrongdoing by the victims.
Ali Kachueian, who lives near the crash site, described the horrific aftermath of the impact: "A lady on the ground. A girl with a bloody face. One person was stuck under the car and one young boy - probably a teenager, actually."
Court records show Attoh has two previous DUI convictions. He has pleaded not guilty to all counts in the Irvine incident and is being held on $1 million bail.
A GoFundMe page has been set up for the surviving family members.