Charles Martin Conlon was born in Albany, NY, in November of 1868, the son of Charles Conlon and Julia Donahue. He grew up in the neighboring city of Troy, NY where he gained an interest in the printing industry and, starting in the 1890s, worked for the Troy Press.

At the turn of the century, Conlon moved to New York City and began working as a proofreader for the New York Evening Telegram, a subsidiary of the New York Herald Tribune. At the same time, he took up photography as a hobby, taking mostly landscape photographs. In 1904, at the request of Telegram editor and Spalding Base Ball Guide assistant editor, John B. Foster, Conlon took photographs at the Polo Grounds. Self taught, Conlon's first photos were blurry or dark but he soon began to master the art of portrait photography. His photos began to be published, uncredited, in the above publications as well as The Sporting News.

In 1907, Conlon married Margaret "Marge" Edwards. The couple did not have any children.

By the early 1910s, Conlon's photos were being widely used in these publications and many others. As technology advanced and Conlon's own skills improved, he began to experimenting with action shots in addition to his portraits. One of his best known shots is of Ty Cobb sliding and is one of the few action shots that has survived to present day. In 1920, he added staff photographer for Baseball Magazine to his many accolades, often still without any credit being given to him as the photographer.

Conlon would continue to take photographs until 1942 when he left behind a legacy as the founder of baseball photography. When Marge passed away, he returned to Troy, NY where he would live until his death on June 2, 1945.