Mortensen spoke to students at Wasatch Elementary School in Clearfield on the 11th anniversary of the terrorist attacks, recounting her brother's achievements in reaching his career goal, while encouraging her young audience to do the same.
"Some people think that Brady is a hero because he died on Sept. 11. I don't. He was just at work," Mortensen said. "What makes him a hero in my eyes is that as a young child, he read books, and he made a goal."
Students at Wasatch Elementary were among hundreds across Utah who paid a somber tribute to 9/11 victims.
Mortensen spoke as part of a ceremony at the school where a historic flag was presented. The flag, displayed in a shadow case, previously flew over the USS Arizona at Pearl Harbor, the U.S. Capitol and at Hill Air Force Base.
Utah Lt. Gov. Greg Bell spoke at the school's ceremony, which began with an Honor Guard and a flag-raising ceremony.
But students appeared particularly moved by Mortensen's story, who described how her brother attended school in New York and later went on to pass the top-secret security clearance needed to work at the Pentagon.
"Brady made sure he was honest and trustworthy," Mortensen said. "He had to live his life in a way that he had to be trusted in order to make his dreams come true."
Mortensen, who rushed to the nation's capital with her 6-month-old daughter after her brother was killed, shared with students information about the country's mood in the days after the attacks and encouraged them to recall how the nation stood united in the aftermath of that day.
She and others read to students in classrooms following Tuesday's ceremony, as part of a reading program launched by the United Way to honor Howell. Students read books inspired by emergency first responders and the military.
Elsewhere, students in the Jordan School District gathered for a sunrise service at South Jordan Middle School for another 9/11 ceremony.
About 300 children joined together to sing patriotic songs around the school's flag pole in observance of Patriot Day.
Today's middle-schoolers were babies when 9/11 occurred, said Shelly Gottfredson, assistant principal at South Jordan Middle School, which makes teaching about the event particularly important to a generation that can't remember firsthand an unforgettable day.
"I would say our goal is that we remember the incident and the event, that we learn to respect others, to appreciate our freedoms and to remember all the sacrifices that were given," said Gottfredson.
Janet Sumner, principal at Wasatch Elementary, agreed that 9/11 is an essential subject to broach with youth.
"I want them to remember our history is an important part of who we are. I want them to know and respect our country's flag," said Sumner. She said following Tuesday's ceremony that several airmen from Hill Air Force Base read with a class of students who struggle. She watched as the students' interest surged when the airmen spoke about their jobs.
"It was so inspirational to show these children what they can do with their lives if they work hard," Sumner said.
Mortensen said she hopes students at Wasatch Elementary were inspired by her words at Tuesday's ceremony.
"What you do now in your life matters," she said. "If you have big dreams and big goals, it's not too early to start working toward those."