In 1849, Ann Tracey and Charles Wilson lived in a house that they owned on Craig Street (now St. Antoine) at the corner of Côte de la Place-d'Armes. They had by then been married for close to 15 years, but apparently had no children. The couple were Roman Catholics, and probably worshipped at St. Patrick's Church, completed not far from there in 1847. Charles Wilson was a prominent businessman and hardware importer; his company, Wilson & Couillard, had its offices in a store-residence on St. Paul Street West, near the Customs house on Place Royale. His associate, A. Couillard, lived on the premises. In the year 1849, the Wilsons were not spared by the outbreak of violent demonstrations when royal assent was given to a bill compensating individuals who had suffered damages during the Rebellions of 1837–1838. Rioters sacked and burned the Parliament, and Wilson's home, like that of his friend Louis-Hippolyte La Fontaine, was severely vandalized during April.

With the turn of the 1850s, Wilson became very active on the Montreal political scene. He was elected a councillor, then appointed mayor by his peers in 1851. During this time, the St. Anne's Market, the seat of the Parliament that had burned in 1849, was rebuilt. In 1852, Wilson became the first elected mayor of Montreal. Under his administration, city hall was moved to the Bonsecours Market. That year was to bring its share of tragedy, however: two major fires broke out . One, the worst-ever of both the 19th and 20th centuries in Montreal, destroyed fully one quarter of the city (mostly the faubourgs), while the other ravaged the heart of the business district (on St. Paul Street around the Customs House). Charles Wilson's hardware business and the Couillard family home were lost to the flames. This led to the Wilson administration decreeing that a regulation enforcing the use of masonry cladding in building construction be extended to the entire city. Under Wilson, city council also voted to begin construction of a new waterworks, a project that had been under discussion for years. Not long after Wilson's re-election in 1853, a sermon by anti-Catholic preacher Alexandre Gavazzi led to a violent confrontation between Orangemen and Irish Catholics, during which police fired into the crowd. Journalists accused Wilson of having given the order himself, a charge which he vehemently denied; nevertheless, he resigned from office that same year.

These events did not keep the couple from pursuing other interests: in the early 1850s, Ann Tracey purchased a vacant lot which had previously been occupied by a store-residence destroyed in the great fire of 1852. She and her husband then undertook the construction of the building that now stands at 105 St. Paul Street West. In 1854, Ann also purchased from her husband's brother, Edward Wilson, a series of store-warehouses that were then under construction along St. Paul Street. Two of these, the twin buildings on either side of St. Lawrence Boulevard, are still standing today. Charles Wilson and Ann Tracey engaged in a number of other real-estate projects, including the construction of another elegant store-warehouse on Notre-Dame Street (the present-day 243–245 Notre-Dame Street West), completed in 1866.