The incident occurred on Camino De Los Mares located west of Calle Nuevo around 1:30 a.m., according to the Orange County Sheriff's Department.
Investigators say a Mercedes sedan was traveling westbound when the driver hit Pasquale who was in the lanes. It wasn't immediately clear if Pasquale was trying to cross the street.
The driver stopped and called 911 but the 20-year-old player was pronounced dead at the scene.
O.C. Sheriff's Department Lt. Jeff Hallock says there is no indication that alcohol or drugs played a role in the incident and that the driver was cooperating with the ongoing investigation. No arrests or citations have been made.
According to the UCLA Bruins website, Pasquale was a redshirt freshman from San Clemente High School, where he was a three-year starter. He wore No. 36 for the Bruins and played in his first college game last Saturday.
The 5-foot-7 receiver earned the nickname "Pacman" from his teammates while participating on the scout team in practices last season and again this summer.
Devastated family and friends gathered at his parent's home Sunday to mourn the walk-on wide receiver's sudden death.
His family says Nick was in San Clemente to watch his high school football team play because UCLA was on a bye.
"He is very well-liked young man," Mel Pasquale, Nick's father said. "His backyard is filled with about 100 people right now. It's a tough sad day but Nick's legacy will live on. I miss him already and I will continue to miss him."
"I'm honored to have had the chance to coach him and our team was honored to have him on the team," UCLA head football coach Jim Mora said. "We're going to go out there every week and every day and we're going to do everything we can just to honor who he was and what he stood for."
On Sunday, UCLA athletic director Dan Guerrero released the following statement: "The UCLA family lost a wonderful young man who represented the university, his team and his family well. Our hearts go out to the Pasquale family, and we will do everything we can to assist and support them, as well as his teammates, as they go through this unthinkable tragedy."
Pasquale's teammates reacted on Twitter as the news of his death came out Sunday morning.
"Love you PACMAN. Brother for life. Bruin for Life," Bruins guard Xavier Su'a Filo tweeted. "The definition of a true team player. Came to practice every day ready to work and give his all for his teammates."
Dietrich Riley, a former UCLA safety whose career ended due to injury this summer, tweeted that Pasquale "took every snap on the scout team. Never complained."
Pasquale was known for his dedication on and off the field. In fact, he had hip surgery when he was 8 years old and was told that he would never play sports again. His family says that was his motivation to prove anyone wrong.
Several hundred people attended a candlelight vigil on the football field of San Clemente High School Sunday night to remember Pasquale.
"Every single thing that Nick Pasquale did, he did it 100 percent and was completely committed to it," said UCLA center and Pasquale's roommate Carl Hulick. "Just the loss that all of us are feeling as a team is absolutely brutal."
"There's never anything he can't do," said Pasquale's brother AJ. "He was a great man, had a bright future, unfortunately cut short. In his short 20 years, he did more than I think I could ever do."
The Associated Press contributed to this report.