What makes a good friend? One man truly knew the secrets of being a good friend to others.

Army Capt. John L. Hallett III, 30, died 13 years ago this Thursday, on Aug. 25, 2009, in southern Afghanistan along with three other soldiers when an improvised roadside bomb exploded. 

Hallett was a West Point graduate. He left behind his wife, Lisa, and their three children (the youngest child, a daughter, was born after Hallett died, so he never got to see or hold her).

"He was assigned to the 1st Battalion, 17th Infantry Regiment, 5th Stryker Brigade, 2nd Infantry Division, Fort Lewis, Wash," according to West Point's website.

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The soldiers were returning from a medical mission after they had delivered medication to stop an outbreak of cholera, a bacterial infection, according to multiple reports. 

John Hallett

Army Capt. John Hallett is photographed during his time in Afghanistan. (Lisa Hallett)

At Hallett's funeral 13 years ago, the church was overflowing because of the number of people who wanted to pay their respects.

His friends were organized into categories because so many wanted to reminisce about stories about him — paying homage to Hallett’s penchant for lists. 

"In any friendship, I believe laughter is a trait that is needed for the relationship to blossom," said Patrick DeGroot, 43, one of Hallett's childhood friends. 

"With John, what was maybe a brief disagreement was no match for a good laugh."

"John was able to be good friends with so many people because he had this characteristic," he told Fox News Digital. 

"As Mark Twain wrote, ‘Against the assault of laughter, nothing can stand,’" he said. "With John, what was maybe a brief disagreement was no match for a good laugh."

Happy-go-lucky kid

John Hallett was born on July 6, 1978, at Cedars-Sinai Hospital in Southern California. His family moved to Pleasant Hill in Northern California when he was 5. 

"We made the move at Thanksgiving, so he made a few friends in Pleasant Hill," his mother, Wendy Swanson Hallett, told Fox News Digital. 

They soon moved to Concord, California, a nearby residential suburb, but young John struggled initially with the move. 

"He had a hard time without any friends," added his mom.

John Hallett and family

Army Captain John Hallett with his wife Lisa and their young children.  (Lisa Hallett)

"The community we moved to was a difficult one to accept new people. In retrospect, I think that is a factor than made him so welcoming and accepting of people," his mother noted.  

"He knew what it was like to not be welcomed into a little group of friends," she said.

Hallett attended St. Agnes Elementary School in Concord, California, from first to eighth grade. He was known as a happy-go-lucky kid with a sprinkle of freckles and not-so-subtle red hair. 

As he started making friends, he picked up gigs on the weekends, doing magic shows for anyone willing to watch.

"He could pull a ‘rabbit out of his hat’ when situations would get tough."

"He loved magic and literally at times could pull a ‘rabbit out of his hat’ when situations would get tough," friend David Adler told Fox News Digital. Adler went to both elementary school and high school with Hallett and was one of his closest friends.

Hallett became a paperboy for the local newspaper and inspired another classmate to follow, all for the privilege of waking up in the early morning hours to deliver newspapers in a bag strapped over their shoulders that felt at times heavier than they were as kids.

Not forgotten: Army Capt. John Hallett, shown here with son Jackson, is remembered along with other fallen soldiers every time members of the group lace up their sneakers.

Much loved and never forgotten: Army Capt. John Hallett is shown with oldest child, Jackson — who today is 16 years old. (Run to Remember)

Hallett competed in basketball during the school year, dreamed about home runs while playing baseball during the hot summers and participated in Cub Scouts, including camping events, as a kid. But one sport defined him: swimming. 

He couldn’t wait for school to end every year to start swimming on the local swim team or spend quality time with his family in the summer lake, perfecting his cannonballs as he proudly modeled his fresh summer buzz cut.

When he entered De La Salle High School in Concord, California, he immediately signed up to play water polo with a set of boys who were equally naïve about the game but just as determined to become great. 

As his circle of friends grew, so did his height. By senior year, he was over six feet tall, but eventually his two younger brothers outgrew him.

"We called him ‘Madgame’ because he was ferocious in all sports he played, especially in [the] water when he swam and played water polo," Adler said.

As his circle of friends grew, so did his height. By senior year, he was over 6 feet tall, but eventually his two younger brothers outgrew him. "But he could always beat them," his mother said. 

After high school, he attended the United States Military Academy at West Point. There, he earned a spot to play water polo for the school during his first year.

West Point

John Hallett attended West Point, graduating three months before the 9/11 terror attacks. He then reported to Fort Benning, Georgia. (iStock)

He confided to his parents that playing water polo allowed him more privileges than many of his other college classmates, so it made it more bearable.

But it was still stressful. 

He proposed to his future wife, Lisa, on Valentine’s Day in 2003 at the top of Diamond Head, a volcanic cone on the Hawaiian island of Oahu. 

His parents encouraged him to call his friends over from the very brief time that West Point allowed him off campus to celebrate his successful milestones there — sometimes by simply watching boxing matches on television.

After graduating three months before the 9/11 terrorist attacks, he reported to Fort Benning, Georgia, for infantry officer basic training, according to the Los Angeles Times.  

Because he had excelled at West Point, he earned one of his top choices for duty station. Hallett reported for duty in spring 2002 at Schofield Barracks in Honolulu, the paper added.

Diamond Head Crater,Honolulu, HI

John Hallett proposed to his girlfriend Lisa in 2003 at the top of Diamond Head on the island of Oahu, Hawaii. (iStock)

He proposed to his future wife, Lisa, on Valentine’s Day in 2003 at the top of Diamond Head, a volcanic cone on the Hawaiian island of Oahu, per the Los Angeles Times.

She spoke to Fox Digital News about how she developed a nonprofit, Run to Remember, in memory of her husband; it has grown nationally since. 

She herself just ran 100 miles this past weekend to help raise money to support "those preparing for a deployment, living through a deployment, recovering from a deployment and healing from loss sustained during a deployment," as her website notes.

Lisa Hallett's simple act of healing has grown into a national nonprofit with thousands of runners.

Lisa Hallett started Run to Remember in her husband John's memory; it is today a national nonprofit with thousands of runners. It honors the service and sacrifice of America's military. (Run to Remember)

She created it as "reminder that freedom isn’t free — it was bought and paid for by men and women in uniform."

Just three weeks after his wedding

John Hallett deployed for a 13-month tour of duty in Iraq in January 2004, just three weeks after his wedding.

After returning to Hawaii in early 2005, he moved in March 2006 to Fort Polk, Louisiana, to serve as a platoon senior observer-controller. 

He reported to Fort Lewis in late 2007, where he served as a battalion personnel officer, assistant operations officer and company commander. 

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He later took command of a Stryker infantry company in November 2008, according to George W. Bush Presidential Center’s website. 

In July 2009, he deployed with his brigade to southern Afghanistan while his third child, Heidi, was born back in the U.S. several weeks later, the website also noted.

John and Lisa Hallett's children,Heidi, Bryce and Jackson, seen here after a Memorial Day road race, will never forget their dad. (Courtesy: Ingrid Barrentine}

John and Lisa Hallett's children, Heidi, Bryce and Jackson, are seen here after a Memorial Day road race. "I run for my dad," their sign says. (Courtesy Ingrid Barrentine/Run to Remember)

He was killed in combat shortly after — without ever meeting his new daughter.

His wife, Lisa, told Fox News Digital this week, "He had a quiet way of doing the right thing — not in a way that was showboating, and not in a way that was condescending toward anyone else." 

She added, "I think in this world today of Instagram and social media, we often have this vision of the picture-perfect life. With John, the beauty of the way he lived was with earnest honesty — and just with his presence and the simplicity of everyday life."

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And "when you were around that," she said, "it made you feel that you wanted to be a part of that."

‘Real, and good, and kind’

"Outside of the water, Hallett was one of the nicest guys you would ever meet," Adler told Fox News Digital.

"He loved being around people and had a very goofy sense of humor. John was always willing to help all of his friends," he added. 

"He was a devoted husband and wonderful father. He is truly missed, but his legacy lives on with his three beautiful children."

Said Shasta Nelson, friendship expert and author of "Frientimacy: How to Deepen Friendships for Lifelong Health and Happiness," "The loss of a friendship is devastating, as it not only takes someone away who we liked but we are losing someone who knew us, who supported us and who built a meaningful shared history with us."

She also told Fox News Digital that "a friendship is formed any time two people both spend consistent time together in a way that leaves them both feeling seen and liked."

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"The more [people] practice the three most important factors in a friendship — consistent time, vulnerability and positive emotions — the closer we’ll feel to each other," she added. 

There is no psychological test for friendships, said Dr. Elie G. Aoun, an addiction and forensic psychiatrist at Columbia University and a member of the American Psychiatric Association board of trustees.

"He treated folks like he wanted to be treated — with dignity and compassion."

"But it is important to surround yourself with people who understand and accept your emotional triggers," he told Fox News Digital.

"Your best friend should know when to push you to take personal, social and emotional risks that will allow you to expand your social and emotional repertoire/status quo."

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As Lisa Hallett told Fox News Digital about her husband, "He showed up as a friend because he was real, and he was good, and he was kind."

Steven Randall, another one of John's good friends, told Fox News Digital, "John would do anything for his friends. He treated folks like he wanted to be treated — with dignity and compassion."