The verdict was reached Wednesday afternoon, nearly two years to the day three people were killed and more than 260 injured in the April 15, 2013, bombings.
His conviction was practically a foregone conclusion, given his lawyer's startling admission during opening statements that Tsarnaev carried out the attack with his now-dead older brother, Tamerlan.
The two shrapnel-packed pressure-cooker bombs that exploded near the finish line, turning the traditionally celebratory home stretch of the world-famous race into a scene of carnage and putting the city on edge for days.
"It's not a happy occasion, but it's something," said Karen Brassard, who suffered shrapnel wounds on her legs and attended the trial. "One more step behind us."
She said Tsarnaev appeared "arrogant" and uninterested during the trial, and she wasn't surprised when she saw no remorse on his face as the verdicts were read. She refused to say whether she believes he deserves the death penalty, but she rejected the defense argument that he was simply following his brother's lead.
"He was in college. He was a grown man who knew what the consequences would be," Brassard said.
The government called 92 witnesses over 15 days, painting a hellish scene of torn-off limbs, blood-spattered pavement, ghastly screams and the smell of sulfur and burned hair. Survivors gave heartbreaking testimony about losing legs in the blasts or watching people die. The father of an 8-year-old boy described making the agonizing decision to leave his mortally wounded son so he could get help for their 6-year-old daughter, whose leg had been blown off.
Killed were Lingzi Lu, a 23-year-old Chinese graduate student at Boston University; Krystle Campbell, a 29-year-old restaurant manager; and Martin Richard, the 8-year-old. Massachusetts Institute of Technology police Officer Sean Collier was shot and killed during the brothers' getaway attempt.
In a statement, Collier's family welcomed the verdict and added: "The strength and bond that everyone has shown during these last two years proves that if these terrorists thought that they would somehow strike fear in the hearts of people, they monumentally failed."
Some of the most damning evidence included video showing Tsarnaev planting a backpack containing one of the bombs near where the 8-year-old was standing, and incriminating statements scrawled inside the dry-docked boat where a wounded and bleeding Tsarnaev was captured days after the tragedy.
"Stop killing our innocent people and we will stop," he wrote.
Tsarnaev's lawyers barely cross-examined the government's witnesses and called just four people to the stand over less than two days, all in an effort to portray the older brother as the guiding force in the plot.
Witnesses testified about phone records that showed Dzhokhar was at the University of Massachusetts-Dartmouth while his brother was buying bomb components, including pressure cookers and BBs. A forensics expert said Tamerlan's computer showed search terms such as "detonator," "transmitter and receiver," while Dzhokhar was largely spending time on Facebook and other social media sites.
The two brothers, who's family emigrated to the USA from Chechnya, ambushed and fatally shot MIT campus police officer Sean Collier days after the bombing before carjacking a motorist at a Cambridge, MA gas station and led police on a high-speed chase ending in a shootout in Watertown, MA after the two brothers lobbed explosives at pursuing officers. An MBTA Transit officer was fatally wounded while Tamerlane Tsaraev was hit by gunfire and run over by Dzhokhar as he sped off in the getaway car. After an afternoon of house-to-house searches, the younger Tsarnaev brother was taken into custody after a Watertown resident discovered an injured Dzhokhar hiding on his boat which was being kept in his backyard.
What remains to be seen is whether or not Tsarnaev will get the death penalty. While Massachusetts hasn't had the death penalty in more than 30 years, Dzhokhar is up on federal terrorism charges and remains eligible for being executed at a federal penitentiary.