In the summer of 1812, with war against England looming, an angry mob of Baltimoreans trapped and tortured a group of British Sympathizers at old city jail. Mayor Johnson arrived in order to quell the situation, where he advised the prisoners and negotiated with the mob. His stance against the instigators was an important political decision as Baltimore, and the United States, moved away from vigilantism. He is also noted for owning the brewery in which Mary Pickersgill sewed the Star-Spangled Banner, America’s most significant flag.
A doctor by trade, Johnson began his medical practice the same year he entered politics. During a serious yellow fever outbreak in 1819, Johnson donated $150.00 of his own money for the publication of a medical report on the epidemic. His efforts proved central in ending the citywide health crisis. An historical tablet, placed across the street from Carroll Mansion, marks the location of his former home. Brewer’s Park, recently replaced with a hotel, was once next door.