Guests stood outside Holy Name Catholic Church, where American flags lined the street.
Houston Mayor Sylvester Turner, Congresswoman Sylvia Garcia, HPD Chief Art Acevedo and HFD Chief Samuel Peña were among those seen outside before the service.
"Even though she has tragically died young, her legacy will be long lasting," Turner said. "Bringing a great deal of change within the military and she's Houston's own. That's what makes us so very proud."
Turner noted that Guillen was part of the Hire Houston Youth program before she joined the Army.
HPD has been providing a special escort for the family, similar to what was provided after the death of Houston native George Floyd.
After the funeral, Guillen's family and friends stopped and appeared to be praying over the casket before doves were released.
Guillen will be laid to rest at Forest Park Lawndale Funeral Home in southeast Houston.
The day before Guillen's funeral, the community was able to say goodbye during the public memorial at her alma mater, Cesar Chavez High School.
Guillen's casket arrived at the school on a horse-drawn carriage that led the procession.
WATCH: Vanessa Guillen's casket arrives at her memorial
Ahead of the memorial's start, Guillen's casket was driven in a hearse from a funeral home for a Veterans Memorial cruise. The casket then was transferred into the horse-drawn carriage along the way to complete the route to the high school, where it took a couple of laps around the campus' soccer field to honor her time playing the sport at Cesar Chavez.
HOW DID WE GET HERE? Vanessa Guillen: The tragedy of her murder and her legacy
On holding the service, Houston ISD said it was honored to help facilitate the memorial:
The Houston Independent School District stands united with the family of U.S. Army Specialist Vanessa Guillen, a proud graduate of Chavez High School. At Chavez, she is remembered as an avid soccer player who was kind, hard-working, and passionate about making a positive difference in the world. Our thoughts and prayers continue to be with her loved ones, including family, friends, former classmates, and former teachers.
During a meeting between Vanessa's family members and President Donald Trump at the White House last month, the president told them that they have his support and that he would personally help with funeral expenses.
"If you need help with the funeral financially, I will help," the president told the family in the Oval Office at the time.
READ MORE: 'I will help': Pres. Trump pledges to pay for Vanessa Guillen's funeral
Before the meeting, family members expressed their purpose on taking Vanessa's story to the top.
"I don't want to hear another woman or man was found dead at Fort Hood. I don't want to hear another woman or man was sexually assaulted, abused or raped," said Vanessa's sister Lupe Guillen.
RELATED: Vanessa Guillen's custom casket donated by designer of Maleah Davis' casket
Ahead of the meeting with the president, several dozen demonstrators joined the family at a rally calling for Fort Hood officials to be held accountable for Vanessa's death and for better investigations of harassment in the military.
"Fort Hood is supposed to be held accountable. Leadership has to be held accountable," said Lupe, while speaking to a crowd outside the U.S. Capitol.
Supporters marched from the rally at the U.S. Capitol to the White House.
WATCH: Vanessa Guillen's family leads rally in Washington
"We are here to demand justice for Vanessa," said family attorney Natalie Khawam.
"Not only does the family grieve, Houston grieves. The nation grieves," said @RepSylviaGarcia. The lawmaker questioned the inspection's report & asked when does the military investigate sexual harassment claims. I'll have LIVE reports this afternoon on #abc13. #vanessaguillen pic.twitter.com/J3OP1otsAF— Steve Campion (@SteveABC13) July 29, 2020
The proposed, #IAmVanessaGuillen bill, would let service members file sexual assault and harassment claims to a third party, rather than their chain of command.
Before Guillen's funeral service Saturday, Congresswoman Garcia spoke about congressional investigation into the Houston native's murder and the bill.
"I will continue working on the bill. It will address a lot of the issues about sexual harassment, how the Army handles missing persons, how the Army is or isn't transparent in the communications with families," Garcia said. "There were a lot of issues raised here, but the important thing today is for the family, the grief, and we all join them in their prayers."
"What we're hearing in many of these cases, and regrettably, there's just too many, is that the solider is afraid of making the complaint because of the fear of retaliation, targeting, chain of position. So it would take it out of the chain of command, and that's a truly critical point," Garcia explained.
The bill comes after hundreds of Fort Hood service members have come forward with their experience on the base.
SEE RELATED STORY: Fort Hood soldier Vanessa Guillen may have been harassed, Army officials said
SEE RELATED STORY: President Trump shares sentiments on Vanessa Guillen's death
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