The 34-year-old Holden has appeared in 513 career NHL games tallying 143 points (45 goals). Furthermore, he's lined up in 55 playoff games including 34 over the past two seasons. In addition to Vegas, Holden has also played for Boston, Columbus, Colorado and the New York Rangers in his NHL career.
"He's a tremendous pro," Senators general manager Pierre Dorion said. "He has a great work ethic, character and leadership. He's more of a defensive defenceman with a great stick and great range.
"He outlets the puck, has played a lot of playoff hockey over the last few years and I think bringing his experience and how he plays the game [makes] him another guy that is going to fit in well with us."
Holden was part of the Golden Knights teams that made the Conference Finals in 2019-20 and the Stanley Cup semifinals last season.
The 2022 third round pick the Sens acquired originally belonged to Vancouver but was flipped to the Golden Knights as part of the Nate Schmidt trade on Oct. 12, 2020.