Arsenio Hilario Sison Lacson Sr. (December 26, 1912 – April 15, 1962) was a Filipino lawyer, journalist and politician who gained widespread attention as 1st to be elected and 15th Mayor of Manila from 1952 to 1962.

[1] Nicknamed "Arsenic" and described as "a good man with a bad mouth",[3] Lacson's fiery temperament became a trademark of his political and broadcasting career.

Despite being a sickly child, Lacson turned to athletics during his time at the Ateneo de Manila University, where he earned a Bachelor of Arts degree.

Lacson pursued his legal studies at the University of Santo Tomas, and after graduating and passing the bar in 1937, he began his career at the law office of future Senator Vicente Francisco.

Before the outbreak of World War II, Lacson also made his mark as a respected sportswriter, cementing his reputation in both law and journalism.

Lacson became popular as a result of his radio show, but also earned the ire of President Manuel Roxas, whom he nicknamed "Manny the Weep".

[10][11] Lacson also wrote columns together with editor José W. Diokno, and writers Teodoro Locsin Sr., and Phillip Buencamino in a newspaper they founded called Free Philippines.

During the two years he served in the House, Lacson was cited by the media assigned to cover Congress as among the "10 Most Useful Congressmen" for "his excellent display as a fiscalizer and a lawmaker".

Representative Lacson successfully unseated incumbent Manila Mayor Manuel de la Fuente in the first ever mayoralty election in the city.

At the time Lacson assumed office, Manila had around ₱23.5 million in debt, some of which had been contracted thirty years earlier, and had no money to pay its employees.

Though the hard-drinking, gun-toting Lacson projected an image of machismo, the author Nick Joaquin observed: Lacson has sedulously cultivated the "yahoo" manner, the siga-siga style, but one suspects that the bristles on the surface do not go all the way down; for this guy with a pug's battered nose comes from a good family and went to the right schools; this character who talks like a stevedore is a literate, even a literary, man; and this toughie who has often been accused of being too chummy with the underworld belonged to the most "idealistic" of the wartime underground groups: the Free Philippines.

The American expatriate and tobacco industrialist Harry Stonehill, who was later indicted by Justice Secretary José W. Diokno for bribing officials, falsely claimed that Lacson had asked him to finance his campaign against Garcia.

[20] When Stonehill refused, Lacson decided not to run, and thereafter, staged a rally at Plaza Miranda where he denounced the United States and what he perceived as the subservience of the Philippine government to the Americans.

"[14] Lacson was considered as the likely presidential candidate of the Nacionalistas for the 1965 election, with his close friend José Wright Diokno as his intended running mate.

Before becoming the justice secretary through Lacson's endorsement, Diokno previously defended the mayor and radio personality for libel charges against his talk show.

[1] Around 5:40 P.M. of August 15, 1962, a hotel boy named Pablo Olazo, who was asked by Lacson to get him some ice, saw him almost at the end of his bed and he was profusely perspiring.

Olazo, then fetched for the aides of Lacson, and later called Mario Tintiangco, his personal physician, but it was Godofredo Banzon, who was the first doctor arrived around 5:50 in the afternoon.

By that time, a secondary physician named Baltazar Villaraza arrived, and he and Banzon thought that the cause of Lacson's death was coronary thrombosis.