 Sleeper was the publisher and editor of the Exeter, New Hampshire," News-Letter", editor and proprietor of "The Lowell Daily Journal" and editor and part proprietor of "The Boston Mercantile Journal".later "The Boston Journal"

Sleeper purchased "The Lowell Daily Journal" on May 15, 1833 and ran the paper in partnership with H. Hastings Weld, however the partnership lasted only a few months resulting in financial distress for Mr. Weld and Sleeper's moving on to work for "The Boston Mercantile Journal.