In the spring of 1838, he engaged in the shoe manufacturing business, in which he continued till the autumn of 1848. During these ten years he annually manufactured from 40,000 to 130,000 pairs of shoes, a large portion of which he sold to southern merchants. One of his southern customers, who owed him more than a thousand dollars, having failed, wrote to him that he could pay him fifty per cent. of his debt, and asked to be discharged. On examining his statement, Mr. Wilson found that several slaves were included in his assets. Here was a question to test his anti-slavery professions. Mr. Wilson promptly signed the papers discharging him from all obligations, and wrote to him, never to send him a dollar of the dividend if it included the money received for slaves. In November, 1839, Mr. Wilson was a candidate for representative to the legislature from the town of Natick, but being a zealous temperance man, and an advocate of the fifteen-gallon law, he was defeated by the opponents of that measure. In the spring of 1840, he took the stump for General Harrison, and during that memorable campaign, made upward of sixty speeches. In 1840, he was married to Miss Harriet M. Howe, of Natick. In 1840, and again in 1841, the people of Natick elected him their representative to the legislature. In 1842, he was a candidate for the State Senate, for Middlesex County, but in that year the Whig ticket was defeated. The next year, however, and in that following, 1844, he was chosen senator. During the session of 1845, the State was deeply agitated by the discussion of the annexation of Texas. In February of that year, a State convention was called to be held in Faneuil Hall, to protest against the annexation. Mr. Wilson drew up the paper calling the convention, for the signatures of the members of the legislature, and applied to every Whig member for his name. The president of the Senate, Hon. Levi Lincoln, and other Whig members, refused to sign the call. Mr. Abbot Lawrence, Mr. Nathan Appleton, Mr. John Davis, Mr. Winthrop, and other eminent Whigs also declined to unite in, or to approve the movement. This was the beginning of that division among the Whigs of Massachusetts on the slavery question, which resulted in an open rupture in 1848, and finally in the utter overthrow of that great and powerful party in Massachusetts. In September, 1845, Mr. Wilson got up a call for a mass convention, in Middlesex County, to oppose the admission of Texas as a slave State. The call was responded to by the people, and at an adjourned meeting in Cambridge, over which Mr. Wilson presided, a state committee was appointed, composed of men of all parties, to procure signatures to petitions against the admission of Texas. Sixty-five thousand names were procured in a few weeks, and Henry Wilson and John G. Whittier were appointed to carry the petitions to Washington.