Bennett's involvement in publishing began when he worked for newspapers in Boston. He then traveled the country as a journeyman printer and established a small newspaper in Northern Michigan. He later returned to Boston to work for Curtis Guild, Sr., who published the market edition of the Boston Commercial Bulletin. He then worked for the Boston Daily Advertiser as an editorial writer. He was widely known for his writings on finance and tariffs. In 1887, Bennett retired from the Advertiser. He founded Frank P. Bennett & Co., which published trade papers, including the American Wool Reporter, later known as the American Wood and Cotton Reporter. In 1891, the company launched the financial publication United States Investor. Along with publishing the magazine, the firm also established an investment information service, run by his son Frank P. Bennett. Jr., that performed research for a fee. In 1895, Bennett's firm was sued by the New York-based William B. Dana Company, which charged that United States Investor's new financial supplement consisted largely of copyrighted content from Dana's The Commercial and Financial Chronicle. "The Chronicle's injunction was granted , protecting the copyright. The case is considered an important one because it has been deemed almost impossible heretofore to protect publications like those of The Chronicle," wrote the Library of Congress' Copyright Office in 1980. United States Investor was published at least through 1921.
From 1886 to 1887 Bennett served as a member of the Everett Board of Selectmen. Bennett was a Republican member of the Massachusetts House of Representatives representing Everett from 1891 to 1894. During his tenure in the House, Bennett was gained a reputation for determinedly opposing any policy he found questionable.
Saugus
In 1894, Bennett moved to Saugus, Massachusetts, and soon became active in town affairs. He served as Town Moderator and on the Board of Selectmen and School Committee. In 1898 he was elected to the Massachusetts House of Representatives. He was a candidate for Speaker of the House in 1900. He ran an aggressive campaign for the position, but was defeated by James J. Myers. In 1903, Bennett returned to the House with the intent of succeeding Myers as Speaker when he retired. That year, Bennett served as Chairman of the House Ways and Means Committee and was a considered a frontrunner to succeed Myers in the next legislative session. However, Bennett decided not to run for reelection and was succeeded by his son, Frank Jr. In 1904, Bennett unsuccessfully challenged incumbent Ernest W. Roberts for the Republican nomination in Massachusetts's 7th congressional district.
