Among the attendees at the Century theater in Aurora, near Denver, was Tom Sullivan, whose son was killed in the July 20, 2012, shooting during a midnight screening of the film "The Dark Knight Rises."
"This isn't only the place we lost Alex," Sullivan told The Denver Post with his wife and daughter. "This is the place we also live. We love to come to the movies."
Aurora Mayor Steve Hogan told the audience the evening showed Aurora's resilience.
"Today, we take another step forward," he told the audience of families, police and local politicians. "We must put aside our differences for a greater good and avoid the use of violence to solve problems."
Gov. John Hickenlooper said, "We certainly recognize all the different paths that people take to mourn, the different paths that people take to recover from unimaginable, incomprehensible loss.
"Some wanted the theater reopened, some didn't," he said. "For many here tonight, though, this is a part of healing."
Since the event was announced, several families of victims said they would boycott the reopening ceremony.
The Post did not report on any boycott Thursday night.
Tom Jenkins, who works in the nearby mall, told the newspaper he wanted the theater torn down.
"I find it disrespectful" for the theater to reopen, he said. "In my view, it's like building a playground on a cemetery."
But Alex Milano, 19, who was in the theater the night of the shooting, told the Post, "If it doesn't reopen, he [the gunman] wins. Plain and simple."
The audience saw "The Hobbit: An Unexpected Journey" after the 40-minute ceremony.
The Post said the theater was guarded on every corner.