"This is a terrible act," he told CNN's Jake Tapper on "State of the Union." "This is the murder of five brave police officers. We mourn them, we stand with their families during this tragedy. And on a broader basis, this is a time for healing."
He also told Martha Raddatz on ABC's "This Week" that "violence is never the answer."
"An eye for an eye leaves everybody blind," he said. "In these times, building bridges, conversations, community relationships between the community, between law enforcement, can and does work."
Johnson added that his department has a role in overseeing local police departments to make sure there is uniformity in tactics.
"Through our grant-making activity, through the encouragement of active shooter training exercises, through financial support, grant support for surveillance, for communications, through training, through our federal law enforcement training center and the like, there is a role for the federal government to play in supporting local law enforcement efforts," he said on "This Week."
New York City Police Commissioner Bill Bratton commented on last week's videos showing police killing black men in Minnesota and Louisiana.
"This is a shared responsibility, trying to bridge these differences that are becoming quite evident through many of these videos that are now becoming very frequent on our TV stations and in the public," he said on "This Week." "We have come a very long way, and I can speak for New York, but quite clearly events this past week show we have really only just begun the journey."
He also defended the Dallas police chief's decision to use a robot to kill the shooter.
"I approve of the chief's decision down there to use that robot so as to not put any additional officers' lives at risk in that circumstance," he said on "This Week." "But the reality is that technology is available to us, the threats that are made against us, and I don't just mean the police, I mean the public. There were innocent civilians shot during that situation in Dallas. So we will review it, we'll take a look at it."