Greever was elected as a member of the Democratic party to the Seventy-fourth and Seventy-fifth Congresses, serving from January 3, 1935, to January 3, 1939; he was an unsuccessful candidate for reelection in 1938 to the Seventy-sixth Congress. He resumed the practice of law, and in 1943 accidentally shot himself while cleaning a shotgun. He died in Cody; interment was in Riverside Cemetery.