Timothy Daniel Sullivan (July 23, 1862 – August 31, 1913) was a New York politician who controlled Manhattan's Bowery and Lower East Side districts as a prominent leader within Tammany Hall.

His father, a Union veteran of the American Civil War, died of typhus in October 1867 at age thirty-six, leaving his wife to care for their four children.

One of them, Alice Roosevelt Longworth, wrote years later in her autobiography about Sullivan, calling him "a tall, well-set-up, smooth-shaven Irishman, who talked a blue streak in the voice and phraseology of the New York-Irish of the East Side...." In her judgment years later,[3] Sullivan was "as straight and well-intentioned and genuinely sympathetic in his personal relations and humanitarian enterprises, as he was callous and corrupt politically.

[6] Along with his political and criminal activities, Sullivan was a successful businessman involved in real estate, theatrical ventures (at one point partnering with Marcus Loew), boxing and horseracing.

[8] Along with various other Sullivans, Big Tim also branched out into popular amusement venues such as Dreamland in Coney Island, where he installed a distant relative, Dennis, as the political leader.

[9] Sullivan, whose control extended to illegal prizefights through the National Athletic Club, influenced the New York State Legislature to legalize boxing in 1896 before ring deaths and other scandals caused the law's repeal four years later.

However, with many residents unable to afford the $3 registration fee issued by the corrupt New York Police Department, his bodyguards could be legally armed while using the law against their political opponents.

[11] Although he had a loyal following, his involvement in organized crime and political protection of street gangs and vice districts remained a source of controversy throughout his career.

In return, they were the recipients of Tammany largesse which included coal in the winter, clambakes and outings in the summer, jobs on the city payroll and all-around assistance.

During the turn of the century, he developed contacts with many influential figures, including Monk Eastman, Paul Kelly, Arnold Rothstein and disgraced NYPD Lieutenant Charles Becker, who was able to obtain for the latter a high-ranking position on the New York police force in 1893.

In exchange, Sullivan had to furnish gang leaders Monk Eastman and Paul Kelly, amongst others, to commit election fraud on behalf of Tammany Hall.

[15] On January 12, 1913, the New York Sun reported in a prominent page two article that he was mourned after being committed, "beyond cure" (without naming illness), suffering from "religious mania".

Finally, after a fortnight, Sullivan was classified as a vagrant and scheduled for burial in Potter's Field despite his tailored clothing and "TDS" diamond monogrammed cufflinks.

And, adding to the speculation of foul play, Thomas Reigelmann, the Bronx coroner and Tammany political appointee who signed the death certificate, failed to recognize the body of his longtime friend despite the lack of trauma to the decedent's face.

[17] Sullivan's wake was held at his clubhouse, located at 207 Bowery, and over 25,000 people turned out for his funeral at St. Patrick's Old Cathedral, New York, on Mott Street.

He was also a main character in Kevin Baker's novel Dreamland, about life in turn-of-the-century New York, set in part in the Coney Island amusement park of the same name.

A fictionalized account of some of Big Tim Sullivan's later years is featured in Dreamland (Kevin Baker), and he plays a minor role in E. L. Doctorow's novel Ragtime.