Denise Schaefer, guidance counselor at Magruder High School, died on May 10. She is with her husband Geoff, an English teacher and coach at Walt Whitman High School, and their children, Hailey, 5, and Katelyn, 3. (Photo courtesy of Melissa McGowan)

Graduation rehearsal at Col. Zadok Magruder High School is Thursday, and Denise Schaefer planned to be there, leading the effort to get the Class of 2014 ready for its momentous end of high school. It was not her paid job, but she stepped up.

Schaefer was like that. Throughout a teaching and counseling career that started in Montgomery County in 1998, she gave her students her time, effort and, as one put it, “her fullest heart.” But at 38, the popular school counselor and mother of two died May 10 from a rare, undiagnosed blood disorder.

Her sudden passing — just four days after she developed flu-like symptoms — cut short a life that was deeply embedded in the worlds of Montgomery County schools and sports. The sense of loss has swept from Magruder, in Rockville, to Walt Whitman High School, in Bethesda, where her husband, Geoff, is an English teacher and coaches swimming and volleyball.

It has touched Olney, too, where Schaefer’s 5-year-old daughter, Hailey, attends Belmont Elementary and where Schaefer was “Coach D,” the mom who had a T-ball team and was the T-ball commissioner for the Olney Boys and Girls Club.

“She was just full of passion for what she did, and she took her job so seriously,” said Katie Peyton Acton, a close friend and Montgomery teacher. “She was radiant and beautiful. . . . She touched people without even knowing it.”

Across the county, there has been a wave of giving back. Gabe Ossi, a family friend, started a fundraising Web site to give Geoff Schaefer support as he raises the couple’s daughters. As word spread through schools and sports clubs, more than 850 people contributed, a sign, Ossi wrote, of something greater than social media.

“This proves the power of a life well lived,” Ossi wrote on the site. “It proves the strength of love and friendship. Just as importantly, this reminds all of us that great educators, whether they be counselors, or teachers, or coaches, are selfless helpers whose impact ripples across the community.”

The effort has raised more than double the initial $50,000 goal.

“She had an impact,” said Lee Evans, Magruder’s principal, pointing out a poster with photos of Schaefer in the main office of the counseling center last week. It was decorated with a big heart and handwritten reflections.

“Heaven gained a new angel,” one message said.

Schaefer arrived at the school in 1998, right out of Gettysburg College, starting out as a math teacher. She also was a class sponsor, a ski club chaperone and a girls’ softball coach for about seven years, rising to varsity coach.

Plans are in the works to dedicate the home dugout to her.

Schaefer turned from teaching to counseling halfway through her career, deciding she was most interested in directly helping students. She was a counselor at Springbrook and Thomas S. Wootton high schools before returning to Magruder.

“She was way more than a teacher,” said Valerie Hassler, a member of Magruder’s Class of 2002, for which Schaefer was a sponsor. “She taught us and she mentored us with her fullest heart.”

Now her office at Magruder is locked. Inside, her jacket still hangs from her desk chair. Everything is just so, as she left it: family photos, records, schedules.

People come by and look in. Some touch the door.

Her colleagues recall her sense of fun, how she revived the lost tradition of a chili and dessert cook-off. They talk about last year’s graduation, when planning fell off track unexpectedly and she jumped into the fray.

“It really went off without a hitch,” said Tim Rossini, a counselor and close friend. “It was her determination and tenaciousness. If she was going to do it, she was going to do it.”

She gave the same full focus to her family.

The Schaefers bought their home in Olney four years ago and felt they’d “hit the jackpot,” Geoff Schaefer said. They loved their neighbors. Denise joined a moms group and got involved in T-ball. She ran the Marine Corps marathon last fall. There was no inkling of how the world would change in May, Geoff Schaefer said.

Even after she fell sick, she called a friend from the intensive care unit, wanting to make sure party favors got to the birthday celebration she planned for her younger daughter.

Katelyn turned 3 the day before her mother died.

Now the community has stepped up in a way Denise Schaefer would have appreciated. Neighbors and friends drop by the Schaefer house to offer help and provide dinner. Along with the online fundraising, other efforts are under way at Magruder and Whitman and at area swim clubs such as Country Glen, where Geoff Schaefer coaches.

And a scholarship at Magruder will be named in honor of Denise Schaefer.

As graduation nears, Stephanie Schwinn, organizing the event without Schaefer, says the much-missed counselor will be in mind during the rehearsal Thursday and the ceremonies at DAR Constitution Hall in Washington on Friday. “There’s a big hole left in our community,” she said.