Born in Katarina Parish in Stockholm, Sweden, Anjou was the natural son of Carl Gustaf Jungberg and his housekeeper Maria Lovisa Hagberg.
[citation needed] Anjou died on March 2, 1942, at Tottenville, Staten Island, and was buried in Fairview Cemetery (at West New Brighton, Castleton Corners, New York City).
[citation needed] He presented himself as a professional genealogist, and his services were employed by many East Coast (USA) families in the late 19th and early 20th centuries.
In 1910, the New York City Directory reported: "British-Am Record Soc, 116 Nassau R [Residence] 1116--C. Percy Hurditch, Pres ; Gustave Anjou.
Anjou initially earned a reputation for providing copious amounts of research to back up his findings, much to the delight of his clients.