Mark Singer, a staff writer at The New Yorker from the age of 23 who extended the magazine’s franchise of rich reporting and witty prose about offbeat, complicated and quintessentially American characters, died on June 26 in Manhattan. He was 75.

Mr. Singer wrote urbane “Talk of the Town” pieces for the front of the magazine, reflected on serious national matters, and did a hitch traveling the country as the correspondent for the “U.S. Journal” column. But he was best known as a profiler. His subjects included the magician Ricky Jay, a set of four doorman brothers in New York, and a braggadocious real estate developer named Donald Trump, years before he ran for office.