(CNN) -- Principal Dawn Lafferty Hochsprung just entered a Ph.D. program. She led a school district's strategic planning panel. She won a national school grant. She could be "a tough lady in the right sort of sense," a friend said.
Among it all, she found time to smile and exuded memorable enthusiasm.
The longtime educator's career seemed to be peaking when she became principal two years ago of Sandy Hook Elementary School in Newtown, Connecticut, which has 525 pupils from kindergarten to fourth grade.
On Friday, Hochsprung, 47, was fatally shot inside her school in a massacre that killed five other adults and 20 students. The shooter killed himself; his mother was found dead in a Newtown house, said a law enforcement source with detailed knowledge of the investigation.
Hochsprung was an affable but serious leader, recalled Tom Prunty, a friend whose niece goes to Sandy Hook and was uninjured Friday.
"She was really nice and very fun, but she was also very much a tough lady in the right sort of sense," Prunty said. "She was the kind of person you'd want to be educating your kids. And the kids loved her.
"Even little kids know when someone cares about them, and that was her," he said.
Hochsprung majored in special education for her bachelor's and master's degrees in the 1990s, and she rose through the ranks, working in elementary, middle and high schools in Connecticut's small communities.
The Connecticut Board of Education appointed Hochsprung as Sandy Hook's principal on June 9, 2010. She came to Newtown with 12 years of administrative experience, including as a principal in Regional School District 14 serving the Connecticut communities of Bethlehem and Danbury, the Newtown Bee reported.
At home in Woodbury, Connecticut, Hochsprung was busy raising two daughters and three stepdaughters.
She also dove into her work, quickly asserting her leadership and implementing a number of initiatives affecting the school's nearly 700 students from about 500 families.
One of them was overseeing the installation of a new security system requiring every visitor to ring the front entrance's doorbell after the doors locked at 9:30 a.m. If they were buzzed into the front office, parents would be asked for photo identification.
Hochsprung also volunteered to be co-chairman of a strategic planning commission for the school district, said Scott Clayton, former assistant principal at Newtown High School, who left this year to become a principal in another district.
The commission post is a weighty, important job, said Clayton, who worked with Hochsprung on the panel.
"She was extremely passionate. And she was especially dedicated to and knowledgeable about curriculum," Clayton said. "This was a deep loss for the community."
Last summer, Hochsprung was one of 15 educators accepted into the doctorate program at Esteves School of Education at the Sage Colleges in New York, the college said.
She was the first person from Connecticut accepted into the 27-month program, said Dean Lori V. Quigley.
Hochsprung made the biggest impression of the group with her smile and enthusiasm, Quigley said.
"She was truly a caring administrator," Quigley said, adding Hochsprung was proud to represent her school.
In 2011, Hochsprung won a school grant called Sharing the Dream from the National Association of Elementary School Principals. The grant creates global awareness in schools and international learning communities.
She proudly posted notes and photos on her Twitter account about her school's activities.
"Setting up for the Sandy Hook nonfiction book preview for staff ... Common Core, here we come!" she wrote on Thursday, her most recent tweet. A photo depicted several children's books, including "Alligator or Crocodile? How Do You Know?"
Another photo shows a choir of boys and girls dressed in white shirts and black pants or skirts being led by the music teacher. The audience was all students.
"Sandy Hook students enjoy the rehearsal for our 4th grade winter concert - a talented group led by Maryrose Kristopik!" Hochsprung tweeted Wednesday. Kristopik is listed as music teacher on the school's website.
On her principal's page of the school website, Hochsprung emphasizes the school's "rich history of establishing high expectations and sustaining strong academic performance."
"Our Responsive Classroom approach focuses on the benefits of a climate of kindness and respect where all community members feel accepted, important, and secure," Hochsprung wrote.
In her two years at Sandy Hook, the principal came across as a "very well-liked, compassionate woman" who was "extremely helpful," said Aimee Seaver, a mother of a first grader.
Hochsprung brought positive energy, sincerity and a strong work ethic to the job -- qualities that will be sorely missed, added Seaver.
"I never saw her without a smile," Seaver said. "I believe she had the children's best intentions (in mind) all the time. She was always looking out for them."
CNN's Lisa Desjardins and Kay Jones contributed to this report.