He notably championed several causes, including reducing the total number of members of the Massachusetts House of Representatives, which at the time stood at over 700, and sponsoring and developing railroad legislation.

During his three years as mayor, the City of Boston underwent significant structural changes, while simultaneously combating rising crime and an influx of Irish immigrants.

To combat this problem, the mayor focused on several high-profile public works projects that he claimed would save the city's taxpayers money and stem the outgoing flow of the rich.

While calling education "the true oasis of our institutions, and the real secret of New England progress and power," he also dismissed the city's recent expenditure of tens of thousands of dollars on the building of new schools.

However, instead of casting blame for the city's crime on the police department's tactics, or the lack thereof, he faulted immigrants and "the intemperate use of intoxicating liquors."

At the time of his inauguration, the mayor estimated that about 60 miles of pipe had been laid underneath the city, providing water to over 5,000 houses and businesses.

By subtracting the number of the city's Irish immigrants from its total population, he argued that Boston's mortality rate had not necessarily increased from the preceding years, nor was it decidedly different from that of small towns.

What differentiated Boston from these small towns, Bigelow wrote, was "its throng of disabled mariners, destitute strangers, and reckless and dissolute persons from every clime."

On August 15, 1849, the Boston Evening Transcript, published an article which highlighted the mayor's actions to remove the infirm to hospitals and educate those who lived in the vicinities of the outbreak about its prevention.

"[10] Bigelow's seemingly successful efforts in combating the city's cholera epidemic had enhanced his political profile, which led some of his supporters to nominate him to be his party's candidate for governor.

"[12] Anti-Irish forces had a powerful spokesman in Mayor Bigelow, who argued that the invasion of immigrants to Boston was causing the city's widespread drunkenness and violence.

He claimed that sympathetic judges were not handing down tougher sentences, charging that the Irish had easy access to pardons because their supporters included the city's influential, lenient, and more charitable members.

[13] In response to the increasing Irish immigrant population, Bigelow once remarked, "Foreign paupers are rapidly accumulating on our hands."

City Marshal Francis Tukey was particularly suspicious of the allegation that on the night of Parkman's disappearance, an Irishman had paid for a one cent toll with a twenty dollar bill.

Another famous case that occurred during Bigelow's tenure as mayor was the Shadrach Affair, which ignited a political and cultural firestorm of controversy, primarily because it involved the Fugitive Slave Law of 1850.

Passed by the US Congress and signed by President Millard Fillmore, the law allowed federal marshals to capture slaves who had run away to non-slaveholding states, such as Massachusetts.

In response to the outrage, Fillmore issued a proclamation that the citizens of Boston, including the mayor, obey the law and aid in the recapturing of Shadrach.

"[14] Anti-slavery forces applauded Shadrach's escape, but they were distressed by the knee-jerk reactions of Massachusetts' politicians, including Mayor Bigelow.

The Liberator wrote several scathing editorials, blasting Bigelow's decision to cave in to the wishes of the president, his secretary of state, and the slave-holding politicians of the south.

"[15] That the Mayor of Boston would be hostile to the freedom and liberty of a slave seems contradictory to understanding the history of relations between the North and the South in ante-bellum America.

However, "the year 1851 still found the bulk of Boston respectability solidly arrayed against the 'fanaticism' which proposed to disregard the fundamental fact of private property in the interests of an impracticable ideal.

This time, Mayor Bigelow acted promptly and forcefully, writing to the colonel in charge of the state militia, "Now therefore, I command you that you cause one or more companies of your Regiment armed and equipped with ammunition, as the law directs, and with proper officers either attached to the troops or detailed by you to parade at said Boston on this and every subsequent day and night until further orders from me at Faneuil Hall."

After being incarcerated for several days, Simms was escorted by more than 100 police officers to a boat in Boston harbor and returned to his master.

Over the course of the next three years, sentiment grew so heated that Anthony Burns, the last escaped slave to leave Boston under the law, cost the city more than $40,000 and the life of one police officer.

A year later, when Daniel Webster petitioned the Boston Board of Aldermen to hold a reception at Faneuil Hall, his permit was denied.

To honor the mayor for his services to the city during the cholera epidemic of 1849, a group of citizens proposed to raise funds to purchase a silver vase.