He played in Major League Baseball (MLB) between 1905 and 1913 for the Philadelphia Athletics, Boston Americans, New York Highlanders/Yankees, and Washington Senators.

Knight was nineteen when he entered the majors in 1905 with the Philadelphia Athletics, playing for them two and a half years before joining the Boston Americans (1907), New York Highlanders/Yankees (1909–11, 1913), and Washington Senators (1912).

Knight was in the Athletics 1905 Opening Day as a replacement for incumbent shortstop Monte Cross, out until mid-season with a broken hand.

Another deal in 1912 sent him to the Senators, who released him to Double-A Jersey City Giants, but he returned to New York in 1913 to finish his major league career.

After that, his frequent travels took Knight to the Minneapolis Millers (American Association); Seattle Rainiers and Oakland Oaks (Pacific Coast League), Denver Bears (Western League) and Sacramento Solons (PCL), before returning to Denver as player-manager in 1928 for his last baseball season.