He was fresh out of school in March 2011, when Syria's uprising began and erased his career plans of treating animals and someday becoming a professor.
As the violence deepened into a civil war, Qadi worked as a medic but later took up arms when his brother was killed, becoming a field commander.
Qadi was leading fighters into battle against the government forces when I met him on two occasions last year, a 25-year-old who was swept up in events he didn't quite understand and didn't expect to survive.
"I try to ask myself where I'll be after the revolution, and I can't imagine myself anywhere but in the grave," Qadi told me the last time I saw him in person.
I saw Qadi again earlier this week: As I sat at my computer in Beirut, a YouTube video flashed across the screen showing his body after he had been killed in northern Syria during government shelling and airstrikes. The video, posted online by the rebels, declared him a "martyr" in the fight against President Bashar Assad.
EDITOR'S NOTE: Ben Hubbard, an Associated Press correspondent based in Beirut, interviewed rebel fighter Abdullah Qadi during reporting trips into Syria. Here is his remembrance of the young brigade commander who died this week while fighting in northern Syria.
Qadi's death was like many of the more than 70,000 in the civil war—violent, fast and mostly invisible to the outside world, other than in a few posts on Facebook pages run by his friends.
For me, it was a moment of recognizing someone familiar in the stream of gruesome images from the nearly 2-year-old conflict.
Because the government bars most reporters from working in Syria, on-the-ground reporting can only be done on dangerous, clandestine trips into the country.
It was on one such trip in November that I spent several days with Qadi and his brigade in northern Syria, both in a simple farmhouse they used as a base near their hometown of Maaret Misreen and in a fancy villa where they squatted while planning to attack an army base.
Qadi fielded my questions about his group, answering softly and earnestly, laughing shyly at times without opening his mouth much to hide a chipped front tooth.
His college education made him different from most of his fellow fighters. He was shorter than many of his colleagues and he usually wore an army green sweater and camouflage pants. He had grown a beard in the revolutionary fashion, but it was too downy to harden his image.
When the political protests against Assad grew more violent, his future was changed forever. Instead of healing farm animals, his medical expertise was put to use in treating victims of the government crackdown.
Then, in December 2011, his brother, Mazen, was killed in a shootout with a pro-regime militia, and Qadi joined a new brigade called The Beloved of Allah, most of whose members were guys he grew up with.
Like most of those fighting Assad's forces, he was a devout Sunni Muslim who didn't fully agree with the jihadists and foreign fighters who had joined the civil war seeking to turn Syria into an Islamic state. But their presence didn't bother him enough to make him refuse their help in battle.
He was popular with his men and known for his caution, recalled Sair Schaib, another brigade member, in an interview via Skype.
Some chafed at times at Qadi's reluctance to push forward quickly, but they later appreciated it. They realized that despite all the talk of the glory of martyrdom, he really didn't want to get his men killed.
This week, Qadi's brigade was among the rebels who pushed into Khan al-Assal, a village east of Aleppo in northern Syria near a police academy that Assad's forces have turned into a military base that regularly fires shells at nearby villages.
Government forces heavily shelled the area and the rebels organized cars to evacuate the civilians, said Schaib, who was a few streets away from Qadi.
Then a government jet bombed them, damaging homes and wounding a number of fighters and civilians.
Once they had been evacuated, Schaib rejoined the rest of his group and found another fighter cradling Qadi's head in his lap and reciting the Muslim declaration of faith.
Qadi's colleagues announced his death on their Facebook page, telling his story in epic language that portrayed him as a model for all.
"He picked up his weapon and joined the valiant revolutionaries, a courageous hero who did not fear death, but instead asked Allah for it, seeking martyrdom and receiving it from Allah," it said. "You will live on in our presence and in or hearts as we continue the march until we reach one of two blessings, victory or martyrdom."
They also posted a video of his body, his face uncovered. His fellow rebels, their voices cracking with emotion, yelled "God is great!"
Qadi was buried Monday night in his hometown, next to his brother.
Months earlier, over a plate of chicken fingers and french fries, Qadi spoke of how he had deferred his dreams of work, graduate study and marriage to fight a war he didn't expect to see end.
But he didn't seem depressed at that late-night dinner. He had fully embraced his new life.
"I'm happy with the battles and the people I've gotten to know," Qadi said. "These are the best moments of my life."