Origin: 1840
The rip-roaring (1834) presidential campaign of 1840, renowned for the "O.K. Clubs" of incumbent Martin Van Buren and the "Log Cabin (1770) and Hard Cider" of successful challenger William Henry Harrison, also introduced the ball that we have kept rolling ever since. One of the features of the 1840 campaign was the rolling of an enormous decorated ball in a political parade. A line in the pro-Harrison Log Cabin & Hard Cider Melodies, published in Boston in 1840, alludes to this practice: "Virginia will keep her ball rolling."
Partisans of the Democratic Party and Van Buren kept their ball rolling too, propelled by men known as ball rollers. "This gang of loafers and litterateurs," wrote one contemporary observer that year, "are said to number 1,000 braves, being the picked men of the old 'huge paws'--'butt enders'--'roarers,' and 'ball rollers.'" Butt enders were enthusiastic young men of the fire department in New York City; roarers were boasters a well as boosters.
The actual ball was soon rolled aside, and ball roller is no longer an avocation, but keep the ball rolling has rolled along with our language to the present day.
Later expressions involving ball came from our twentieth-century enthusiasm for sports other than politics. Americans were the first to keep our eyes on the ball (1907) and to be on the ball (1939).