The 14-year NHL veteran was an unrestricted free agent. He was captain of the Philadelphia Flyers last season and was captain of the Edmonton Oilers the five previous seasons.
"I had offers from other teams but as a family option and an opportunity to move forward, Ottawa was something that was very interesting to me and my family," Smith said.
Smith joins a team that's dressing room chemistry was called into question last season and he was asked about his reputation for not being afraid to get into the face of a teammate.
"Whatever you can bring to the team to help the team do well is what you need to do, whether that's yell and scream or sometimes guys just need a pat on the back," Smith said.
"There's different situations," he added. "There's a lot of things needed to be dealt with amongst the players in the dressing room. Every situation is different. I think when a dressing room is functional and the guys are working hard and playing hard, a lot of that stuff keeps itself straightened out and you don't have to really deal with that."
The 34-year-old Smith led the Flyers with 204 blocked shots and 142 hits in 77 games last season. He also had one goal and nine assists and 86 penalty minutes.
Smith has 40 goals and 128 assists and 1,052 penalty minutes in 945 career games with the New Jersey Devils, Toronto Maple Leafs, Oilers and Philadelphia.