He played in Major League Baseball (MLB) from 1912 to 1925 for the Washington Senators, Boston Red Sox, and New York Yankees.

Regarded as one of the better defensive players in baseball, Shanks began his MLB career as an outfielder, but he also played as shortstop for Washington and as a utility infielder for Boston and New York.

His father, Samuel Shanks, immigrated to the United States from Ireland and lived in Youngstown, Ohio, before moving to Chicago.

Shanks played for a semi-professional team in Rochester, Pennsylvania, in 1908 that was run by former Major League Baseball player Tom McCreery.

"[7] The Pittsburgh Pirates expressed interest in selecting him in the upcoming Rule 5 draft, but after seeing his medical report, they opted not to.

When Moeller returned to the Senators, he played as a right fielder, with Tilly Walker becoming a bench player.

[15] On May 31, 1913, Shanks sprained his right ankle sliding into home plate during a game, and was taken to Georgetown Hospital for treatment.

[17] By the 1914 season, Senators manager Clark Griffith said "Howard Shanks is, in my mind, the greatest fielding outfielder in baseball".

[19] In 1915, Griffith brought in Henri Rondeau, Bill Brown, and Red Massey to compete with Shanks for playing time in an attempt to improve the team's offensive output.

[20] Rondeau made the Senators roster for the 1915 season and was given a trial in left field,[21] but was sent to the minor leagues in May.

[1][31] The Senators traded Shanks, Ed Goebel, and Val Picinich to the Boston Red Sox for Muddy Ruel and Allen Russell on February 10, 1923.

[37] Shanks signed a contract with the Louisville Colonels of the Class AA American Association for the 1926 season as their regular third baseman.

[42] Before the 1928 season, Shanks became a coach for the Cleveland Indians of the American League under manager Roger Peckinpaugh.