Raymond Cormier has been found not guilty of second degree murder in the August 2014 death of Tina Fontaine.
Cormier was charged with second degree murder in connection with the August 2014 death of Fontaine, 15.
The teen's body was found in the Red River, wrapped in a duvet cover.
The jury received its charge Wednesday after a three-week trial.
The Crown had argued Fontaine's death was caused by smothering or by being placed in the river while she was still alive.
Cormier's lawyers said he should be acquitted because the Crown hadn't proven beyond a reasonable doubt Fontaine’s death was caused by an unlawful act.
The jury's verdict came after 11 hours of deliberations.
Court of Queen's Bench Chief Justice Glenn Joyan addressed the court prior to the verdict, saying that the trial was "an emotional one" by nature, and that anyone who is unable to keep emotions in check should leave.
People in the courtroom gasped as the not guilty verdict was read, and the great-aunt who raised Fontaine cried, before being comforted in the halls of the court building.
First Nations leaders spoke outside the courtroom afterward, saying all levels of society let Fontaine down.
Sheila North, Grand Chief of Manitoba Keewatinowi Okimakanak, said "This is not the outcome anybody wanted. The systems, everything that was involved in Tina's life failed her."
"All of us should be ashamed of what happened to her and to Colten Boushie," North said.
Assembly of Manitoba Chiefs Grand Chief Arlen Dumas asked how reconciliation can take place without justice.
Chief Justice Joyal tells Cormier he will be discharged. Lots of people now gathered in the halls of the courthouse comforting Favel. There were a few choice words directed at Cormier after the verdict came down
— Josh Crabb (@JoshRCrabb) February 22, 2018
Mb Chiefs demanding justice for #tinafontaine “All of us should be ashamed of what happened to her and Colten Boushie” @CTVNews pic.twitter.com/39NBbcb5k2
— Jill Macyshon (@JillMacyshonCTV) February 22, 2018
Winnipeg’s mayor also released a long statement reacting to the verdict.
Mayor Brian Bowman said Fontaine’s death was a tragedy, and that “Winnipeggers and Canadians may have differing views on today’s outcome in this case. I think it is important, however, to be mindful that for many people, today is a day marked by grief, anger, and broken hearts.”
Bowman went on to say, “No one can be blind to the racial tensions in our country,” and that “All of us have a responsibility to challenge racism and discrimination when we see it.”
Read the full statement here:
Minister of Crown-Indigenous Relations and Northern Affairs also reacted to the verdict, on Twitter.
My thoughts are with Tina Fontaine’s family. Tina's is a tragic story that demonstrates the failures of all the systems for Indigenous children and youth on every level. We need to do better – we need to fix this
— Carolyn Bennett (@Carolyn_Bennett) February 22, 2018
Meanwhile, Winnipeg police said officers would not comment on the outcome of the trial, except to say that in general after a trial, police will examine the case to "determine if an appeal is possible or appropriate."
A statement from the service also said police "...understand that this is a difficult time for Tina Fontaine’s family, our community, and all those personally affected by her loss. Our thoughts today are with everyone impacted by this tragedy."
With files from CTV's Josh Crabb, Jill Macyshon, Jon Hendricks and Megan Benedictson and The Canadian Press.
