The film stars William S. Hart, Eva Novak, Leo Willis, Alfred Allen, Bert Sprotte, and Antrim Short.

In 1921, the Motion Picture World summarized,"O'Malley of the Mounted" is a sergeant who has won his stripes by getting any criminal he is sent out to arrest, this in wild Northwestern territory amid men who dare follow their own impulses rather than obey the law.

According to Motion Picture World, the film concludes:By Rose and Bud the sergeant is rescued from sure death.

While riding with them toward the border he confirms his suspicions that Bud is the murderer he is seeking, but finds that the killing was done to avenge a wronged sister.

He leaves the brother and sister to make his report, and finds his act justified by his commanding officer.