Also during his tenure as health commissioner, a 1921 decision by the Supreme Court of Illinois greatly weakened the authority of the office.

[6] Robertson organized the American College of Medicine and Surgery in 1900, and was its president until it merged with Loyola University Chicago's own medical school.

[14] The first local diagnosed cases occurred at Great Lakes Naval Training Center in North Chicago, Illinois, on September 8,[15] and, despite all leaves being canceled for enlisted men, the flu found its way to the City of Chicago two weeks later, likely as visitors had not been prohibited at the training base.

[13] On September 21, brushing off fears of the flu spreading from army camps into the city's general population, Robertson declared, "I see no cause for public alarm, but every one developing any symptoms should be careful.".

[13] On September 23, due to the number of new cases decreasing at Great Lakes, but at only the beginning of Chicago's outbreak, Robertson insisted that, "We have the Spanish influenza situation well in hand now.

[17] Howard Markel has provided historical analysis which has found that the rate of truancy was so great, that, in regards to the spread of the virus, it "really didn't matter" that schools remained opened, since so few pupils were actually attending classes.

[16] Robertson advised interim general superintendent of the Chicago Police Department John Alcock to have officers stop all "persistent sneezers and coughers" that failed to cover their faces with handkerchiefs.

Violators that pledged to obey instructions in the future would be released, but individuals who gave officers trouble would be arrested, lectured on the hazards of the flu, and sent to a judge for arraignment.

[15] Robertson warned the managers and owners of theaters to make sure their consumers used handkerchiefs, threatening to otherwise close their businesses.

[15] Churches, schools, theaters, restaurants, streetcars, and other locations in which people gathered were ordered to maintain proper ventilation.

[14] On October 15, theaters, cinemas, skating rinks, night schools, and lodge halls were ordered closed.

[23] On October 12 the Emergency Commission recommended that the Chicago Surface Lines leave streetcar front doors open in order to allow a constant stream of fresh air to enter the cabins.

[23][20] In November, by which time the Spanish Flu had already greatly infected much of the population and had begun to recede, restrictions were loosened.

[25] The lawsuit was raised by Jennie Barmore, who was being forcefully quarantined as an asymptomatic carrier of typhoid at the orders of Robertson and health commission epidemiologist Herman Bundesen.

[6][34] In the weeks preceding his appointment by Small, Thompson had organized a "coup" in which he the majority of the board to elect John C. Kruse as its president.

[6] He ran first as an opponent in the Republican primary, but withdrew to support Edward R. Litsinger's campaign (at the request of Frederick Lundin).

[42] After Thompson won the Republican primary, Robertson reentered the race as a third-party candidate, running on a "smash crime rings" platform.

[43][44] At a rally on March 28, 1927, Robertson announced that, if elected, he would appoint former United States attorney Edwin A. Olson as police chief.

[47] Robertson ran on the ticket of his newly-founded "People's Ownership Smash Crime Rings" party, and included Cook County Coroner Oscar Wolff on his party's ticket as its nominee for city treasurer of Chicago and Charles J. McGowan as its nominee for city clerk of Chicago.

[50] Robertson was also supported by the incumbent 43rd ward alderman Arthur F. Albert,[51] whose opponent Titus Haffa had endorsed Thompson.

[53] Despite Thompson's popularity with African American voters, there were Edward Herbert Wright-aligned Black Republicans who publicly backed Robertson.

[55] In 1930, Robertson resigned as President of the West Parks Board to become the safety and medical director of the Motorists' Association of Chicago.

[6][7][56] At notable incident that occurred while he was safety and medical director for this organization was a fist fight he got into with Sidney Gorgham, director of the Chicago Motor Club, at a heated committee hearing of the Illinois General Assembly where Robertson was lobbying on behalf of a law relating to driver's licenses.