She grew up in Cedar Lake, Ind., and her family said she died doing what she loved.
The whale, Tilikum, will remain on exhibit at SeaWorld and continue to work with trainers.
"We have every intention of continuing to interact with this animal, though the procedures for working with him will change," SeaWorld said in a post on its blog.
Tilikum had been involved in two previous deaths, including a Canadian trainer dragged under water by him and two others whales in 1991.
SeaWorld said it is reevaluating safety procedures in light of the accident and killer whale shows have been suspended indefinitely in Orland, where the accident happened, and in the park's San Diego location.
Authorities said trainers had to lift the whale out of the water before they could free Brancheau from its jaws. A trainer said the whale was lying in front of the 40-year-old when he saw her braided hair and grabbed onto it. A horrified noontime crowd watched.
She likely died from multiple traumatic injuries and drowning, the medical examiner's office said.
Indiana family, community celebrates her life
Her family in Northwest Indian said Brancheau was living her dreams by working with the whales at SeaWorld. That's evident, her family said, in the photos of Brancheau that were used in promotional materials for the park.
" You could just tell by just looking at her face. She smiles from ear to ear. She loves what she is doing," said Diana Gross, Brancheau's sister. "We all felt he had the most awesome job in the world. Our kids grew up visiting her, seeing her shows, seeing what she does and we were just so proud of her."
Thirty years ago, Brancheau's family visited SeaWorld. That's when she knew she wanted to train whales, according to Gross, so she researched the education and experience it required. Then, she went out and did it.
"She talked about it her whole life. She knew she wanted to work with the animals and SeaWorld was her dream," said Gross.
Brancheau's family is taking solace in knowing how much she loved her job. Her success was also celebrated in the community- and came as no surprise to those who knew her at Andrean High School in Merrillville, Ind., where she was study body president, a cheerleader and homecoming queen.
"Every parent knows that their child is special and thinks their child is special. And I just want her parents to know that everybody felt that way about Dawn. She was just very special to all of us," said Donna Bombassaro, IT teacher.
"I would want Dawn remembered the way she was, being a very happy sociable person, somebody that I guess you could say lived life as much as you can," said Mark Horvath, economics teacher.
After high school, Brancheau studied psychology and animal behavior at the University of South Carolina. She then took progressively senior training jobs at water parks around the nation, all in pursuit of getting back to SeaWorld. In the mid 1990s, she was hired.
In the past year, Andrean High School featured Brancheau in the school's annual alumni magazine, which focused on defining and pursuing dreams.
"She just gave you this huge smile and that's the picture I hold in my mind now. That smile, whenever she met any person in her life," said Father Paul Quanz, principal.
Tilikum also blamed in 1991 and 1999 deaths
Because of his size and the previous deaths, trainers were not supposed to get into the water with Tilikum, and only about a dozen of the park's 29 trainers worked with him. Brancheau had more experience with the 30-year-old whale than most. Chuck Tompkins, who is in charge of training at all SeaWorld parks, says the park believes he is the biggest male killer whale in captivity.
Tilikum was one of three orcas blamed for killing a trainer in 1991 after the woman lost her balance and fell in the pool at Sealand of the Pacific near Victoria, British Columbia.
A few months later, SeaWorld asked the U.S. National Marine Fisheries Service for permission to bring Tilikum to Orlando temporarily, according to agency documents obtained by The Associated Press. The agency is responsible for issuing permits to bring orcas and other marine animals into the U.S.
In a Jan. 8, 1992, letter, the agency said SeaWorld wanted to bring Tilikum to Orlando to provide medical treatment and care unavailable in Canada. The letter does not specify Tilikum's medical condition, nor does it mention his role in the deadly attack on the trainer.
Nancy Foster, director of the agency's office of protected resources, said in the letter to Brad Andrews, SeaWorld's vice president of zoological operations at the time, that "prudent and precautionary steps necessary for the health and welfare of Tilikum were not taken by Sealand or SeaWorld."
Despite that, the documents show SeaWorld Orlando got permission in October 1992 to permanently display Tilikum and the two other killer whales involved in the Canadian trainer's death. Both of the other whales have since died.
Tilikum was also involved in a 1999 death, when the body of a man who had sneaked by SeaWorld security was found draped over him. The man either jumped, fell or was pulled into the frigid water and died of hypothermia, though he was also bruised and scratched by Tilikum.
Gross, said the trainer wouldn't want anything done to the whale.
"She loved the whales like her children, she loved all of them," said Gross, of Schererville, Ind. "They all had personalities, good days and bad days."
Celebrity zookeeper Jack Hanna said he has known Brancheau professionally for the last 10 years and also believes she would not want anything to happen to Tilikum.
Brancheau's passion for marine life began at age 9, Gross said, on a family trip to Sea World.
According to a profile in the Orlando Sentinel in 2006, she was one of SeaWorld Orlando's leading trainers. She also addressed the dangers of the job.
"You can't put yourself in the water unless you trust them and they trust you," Brancheau said.
Although Brancheau had a long history with SeaWorld's largest orca whale, homicide investigators suspect her ponytail may have brushed the whale's nose triggering the attack.
"He probably recognized, it may have touched his nose or rostrum as we call it. He may have sensed it was there. Or he may have seen it. But it could have been a fascination to him," said Chuck Thompkins, SeaWorld curator.
But some experts take another view.
"Killer whales, because they're supposed to be so intelligent, don't do things accidently. This was not an insane uncontrollable act. This was premeditated," said Richard Ellis, marine conservationist.
It was not the first attack on whale trainers at SeaWorld parks.
In November 2006, a trainer was bitten and held underwater several times by a killer whale during a show at SeaWorld's San Diego park. He escaped with a broken foot.
In 2004, another whale at the company's San Antonio park tried to hit one of the trainers and attempted to bite him.
Wednesday's attack was the second time in two months that an orca trainer was killed. On Dec. 24, 29-year-old Alexis Martinez Hernandez fell from a whale and crushed his ribcage at Loro Parque on the Spanish island of Tenerife.
The Associated Press contributed to this report.