The public memorial service was held at the Calvary Community Church in Westlake Village.
After the service, a short procession took place and a graveside service was held at Pierce Brothers Valley Mortuary and Cemetery.
Pastor Steve Day of Calvary Community Church opened the service for Helus by calling for a standing ovation to honor how the sergeant touched people's lives.
"Sgt. Ron Helus served for 29 years with integrity," Day said. "That's what we all hope to do in whatever we do."
Day recalled how Helus met his wife Karen while the two were students at Pierce College in the late 1970s. Ron helped her studying in an anatomy class.
They later went on their first date on Nov. 15, 1987 - 31 years to the date before his funeral.
He proposed to her on Sept. 3, 1988 when they went out to a restaurant that was then called Charlie Brown's.
The same site was to later become the Borderline Bar & Grill, where Helus was killed.
Day recalled that Helus had slipped the engagement ring into Karen's purse while they were out to dinner. She found it in her purse while in the bathroom and thought someone else's ring had fallen in there.
"She comes out of the bathroom, comes up to Ron, 'Look at this.' And she opens it up. And Ron gets down on one knee right there in the restaurant. Asked her to marry him. History."
"They were in the old Charlie Brown's restaurant. Which is now the Borderline. How ironic."
Singer Billy Ray Cyrus performed in the service, singing "Amazing Grace" accompanied by a chorus and then his own song "Some Gave All" which honors those who died in service of their country.
"Today we're here to honor this hero, Mr. Ron Helus, that's touched us all here in America, touched the world," Cyrus said.
"I met the family earlier and I told them that they're probably going to need to change the definition in the dictionary of hero. I think from now on it can be a picture of Ron Helus and his bravery. This man's the true definition of hero."
Lauren Smith, Helus' niece, said her uncle was always protective of his family and friends, and that he valued people and experiences.
"In the last few days our family has experienced an outpouring of love that is nothing short of inspiring," Smith said. "We are overwhelmed by the level of care and sympathy that this community, our community, has shown us. My family's world has been shaken by the loss of a husband, a father, an uncle, a brother, a nephew, son and dear friend. We mourn with all of the others who lost their loved ones."
Helus, 54, rushed into the bar moments after gunfire erupted, immediately engaged the shooter in a firefight and saved at least four people before he was shot and fatally wounded on Nov. 7. In all, 13 people died, including the gunman, who killed himself.
A 29-year veteran of the Ventura County Sheriff's Department, Helus was described as a hero by Ventura County Sheriff Geoff Dean.
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Dean said Helus was planning to retire within the next year.
An avid fly fisherman who loved the outdoors, Helus posted photos of himself and his son fishing on his Facebook page, which since his death has been set to legacy status. At work, he took on many of the sheriff's department's toughest assignments, working on the SWAT team and in narcotics and investigations.
Helus is survived by his wife, Karen, and son, Jordan.
The Associated Press contributed to this report.