The one-kilometre trek began after speeches from Sharon Johnston, wife of Gov. Gen. David Johnston, and Phil Marsh, regional manager of the local Running Room stores.
Three people were killed and more than 180 were wounded when two bombs exploded just blocks away from each other near the finish line of the Boston Marathon last Monday.
Officials said 50 people remained in hospital as of Monday, including some in critical condition. Some people were forced to have their limbs amputated as a result of their injuries.
Dylan Wykes, a long-distance runner from Kingston, Ont., who competed at the 2012 London Olympic Games, led the walk.
Ottawa-Centre MP Paul Dewar addressed the crowd, calling it a "proud day" for Ottawa. He said runs are a celebration of civic spirit, community and individual strength.
"People tried to take that away, but what we've seen in the last number of days is that people have come together," Dewar said. "More people are participating in runs. More people are coming out to say that we will not turn our backs, we will not hide, and we will continue to look out for each other. So today we see this in Ottawa."
U.S. Ambassador David Jacobson spoke to the walkers once they reached the embassy.
"I want to thank all of you, every one of you, for coming out today, and all the people all across Canada who participated in events like this over this last week," Jacobson said.
"Exactly a week ago … a very cowardly act took place, an event that shocked and touched every one of us.… But literally, from that moment forward, we watched another side of human nature unfold, the side with our better angels."
Jacobson's speech was followed by a minute of silence.
A minute of silence was also held across Massachusetts at 2:50 p.m. ET Monday, which is when the first bomb exploded .