Dzhokhar Tsarnaev, 19, suspected to be behind the twin blasts at the Boston Marathon early this week was arrested after an exchange of gunfire with the police in which his accomplice brother was killed.
He was captured from a boat, where he was hiding, authorities announced.
Dzhokhar, who was bleeding, was taken to a hospital and was in serious condition, the police said.
Three people were killed and more than 180 others were injured when two bombs, inside pressure cooker, went off in quick succession on Monday amidst thousands of people near the finish line of the Boston Marathon.
The State police said Tsarnaev was hiding in the boat parker in the backyard of a house in Water Front neighbourhood of Boston.
The police said they were first informed about the suspect from a resident of the area, who saw blood stains near the boat.
"He opened the tarp and saw a man covered in blood," a police official said. The man retreated and alerted law enforcement officials.
Dzhokhar was injured when the police shot dead his elder brother Tamerlan Tsarnaev, 26, outside the same neighbourhood.
Dzhokhar had managed to escape from there.
"Captured!!! The hunt is over. The search is done. The terror is over. And justice has won. Suspect in custody," Boston police department said on Twitter after Dzhokar was arrested.
The arrest was later celebrated by hundreds of people, who descended on to the streets of Boston chanting, "USA! USA!"
In his address to the nation, US President Barack Obama, hailed law enforcement officials for their bravery and hard work over the last five days.
"We are extremely grateful," he said in his live address from the White House.
"Whatever they (terrorists) thought they could achieve, they failed," because, "as Americans we refuse to be terrorised", Obama said.
Obama assured the nation that unanswered questions from the tragic incident as to why and how this incident happened will be answered.
"Why did young men who grew up and studied here resort to such violence?" Obama said this is another question that he would like to get answer to.
"We've closed an important chapter in this tragedy," Obama said.
Earlier during a news conference in Boston late last night, Boston Police Commissioner Ed Davis, said that Dzhokhar was in serious condition in the hospital.
The House Speaker John Boehner said it was a job well done under trying circumstances, to say the least.
"We are also proud of the people of Boston and Watertown for showing great resolve and assisting authorities throughout the ordeal," he said.
"This has been a long day and a long week, but along the way we have gained many examples of courage and character," Boehner said.
US House Homeland Security Committee Chairman Michael McCaul said the attack on the Boston Marathon is indicative of the shift in terrorists' tactics in recent years to inspire people who are living in the US to strike.
"While several plots of this nature have been thwarted, this is the first to succeed. Americans must not back down in the face of terrorism, and we will continue to look for those would attempt to do us harm," he said.
The Justice Department said that the suspect has not been read Miranda rights, a warning that is required to be given by US police before interrogation.
The FBI Director, Robert Mueller, said the investigation will continue as part of the efforts to seek answers and justice, and there will be no pause in that effort.
"The apprehension of the suspect tonight is a significant development in the ongoing FBI-led investigation of the Boston bombings," Homeland Security Secretary Janet Napolitano, said.