Clouston replaces Craig Hartsburg, who was fired Sunday night after Ottawa slipped to 17-24-7. The Senators are last in the NHL Northeast Division and 13th in the Eastern Conference.
Clouston, who had been head coach of the Binghamton (N.Y.) Senators of the American Hockey League, will make his NHL debut Tuesday night against the Los Angeles Kings. Murray said Clouston will coach the Senators for the rest of the season.
"We had fairly high expectations this season," Murray said. "We also believed that we would rebound from a shaky start. We kept hoping there would be some change in our performance, which didn't seem to be taking place."
Clouston compiled a 59-48-12-8 record in Binghamton after spending five seasons as head coach of the Western Hockey League Kootenay Ice. The native of Viking, Alberta, went 209-111-24-15 with the Ice, guiding them to five straight playoff berths, including a run to the conference final in 2004-05.
He was the WHL coach of the year in 2006-07 prior to joining Binghamton.