Hip Sing Tong Headquarters Mock assumed the role of leader of the Hip Sing Tong in 1907. When he joined Hip Sing, he was dubbed "Mock Duck," likely for its allusion to the meat-substitute and, because when the roman letters spelling "duck" is pronounced in Cantonese, its sounds is analogous to a Canton word meaning "righteousness."

On Leong Headquarters, a rival of the Hip Sing Tong. Chinese tongs were "controlling agencies of the highly independent settlements which form the Chinatowns of a score of great American cities," according to a profile on Sai Wing Mock in the New Yorker. Though it was assumed that these organizations were carried over from groups overseas, "the tong... does not exist in China. It is as American as the coon-skin cap of Daniel Boone and would be superfluous in China today. But over here it is as necessary...as the stockade was from the point of view of early Puritans." ("Tong Leader." New Yorker. December 30, 1933.)

The "Bloody Angle," nicknamed for constant violence that occurred on this crooked street. Though Mock was born in the United States, he was incredibly traditional in his practices and values. This was reflected in how he kept his appearance. Mock wore a long ponytail, even while other Cantonese men began cutting theirs short following the 1911 Revolution, which overthrew China's last imperial government. Mock prowled Chinatown "covered in diamonds...his sinister image bolstered by his long, lethal-looking fingernails, which signal he is too grand to do the dirty work he assigns to others," according to historian Bruce Edward Hall in Tea That Burns: A Family Memoir of Chinatown.

The Chinatown Tunnels, a hotbed of illegal activity, had an entrance on Doyers Street. Mock quickly became a featured figure in the news, with illustrators for various newspapers capturing his appearance. He was written up about twice a year in police reports and was constantly on the stage of current events. In one appearance in court, Mock wore a "neat business suit, high yellow shoes, and a silk shirt. In his cravat and on his left forefinger were large diamonds." The man was never one to dress down.

Mock Duck was tried multiple times for a murder that occurred at 23 Mott Street, at the left, where a Chinese tailor was slain. Mock became so notorious that the police arrested him every time a Chinese person in New York City was killed. For many years, the On Leong Tong and the Hip Sings were engaged in battle. The two tongs both operated opium dens and gambling rings throughout the city. Seeking to take down the On Leong's from the inside, Mock collaborated with a Tammany Hall opponent, Charles Parkhurst, to give the and address of his rival's establishments. They were shuttered immediately, raising the Hip Sings to status as a prominent tong.

Port Arthur Restaurant, where the Tong War Peace Treaty of 1906 was signed. Though Mock and On Leong leader Tom Lee signed a truce at Port Arthur, one of the most lavish restaurants in Chinatown, in 1906, the tongs entered war once again from 1909 to 1910. Following the war, Mock was arrested and sent to Sing Sing Correctional Facility from 1910 until 1912 for operating an illegal numbers game. Even after his release from prison, Mock remained leader of the Hip Sings, though he lived a relatively quiet life away from the violent skirmishes of Doyer's street. He reverted to using his given name, Sai Wing Mock, much to the confusion of other Cantonese-speaking rivals and local law enforcement. In 1932, Mock agreed to declare peace among the Tongs after an arrangement between the U.S. and Chinese governments. He retired to Brooklyn, where he spent the rest of his life in relative solitude.