Home from St. John’s after graduation, Joseph helped run the family farm, Prospect Place, located two miles outside of Yankton. Joseph began in earnest pursuing a writing career and with the editing assistance of his mother, submitted many articles for publications to newspapers and periodicals. Unable to earn a sustainable living from his writing and with the family in need of financial support, Joseph sought work outside of Yankton.  With the influence of his Uncle Abe Mills, a Vice President with Otis Elevator in New York, Mr. Comstock of Otis hired Joseph as a salesman for the Chicago office in March 1900.  Shortly upon arriving in Chicago, the company transferred him to the St. Louis office, where he worked until December 1908.  He declined a promotion, which would have sent him to Oklahoma, to return to Yankton.

     During the eight years Joseph lived in St. Louis, he continued his writing efforts submitting poetry, articles, and stories to national magazines and the local St. Louis newspapers, receiving as many rejections as acceptances.  He was a contributor to the Missouri Historical Society Magazine.  He began researching and writing his first book, The Conquest of the Missouri, a non-fiction work about steamboating, centering on the life of Captain Grant Marsh, which McClurg & Co. published in 1909.  Joseph was witness to the building and completion of the St. Louis World's Fair and it was at the fair that he met his first wife, Frances Johnson of Holden, Missouri.  After their marriage, Joseph and Frances lived at Prospect Place.  Due to the demands of farming, Joseph could only continue his writing during the winter months. 

     In 1916, the SD National Guard called him for active duty in San Benito, Texas where he served as captain with Company M 4^th Infantry.  Deactivated but later reactivated in 1917, Joseph served with the 147^th AEF, Captain-Adjutant 2^nd Battalion, in France during WW1 where he was placed on the writing staff of the Stars and Stripes as first officer in charge of Historical Sub-Section.  After the war, Joseph remained in Europe as special writer for the Stars and Stripes to write the History of the American Combat Division.  He also spent time researching the history of the countryside along the Marne River, which resulted later in publication of a book, The Marne, Historic and Picturesque.   During his time in Europe after WWI, Joseph represented GHQ at the organization convention of the American Legion in Paris, March 1919.  With the AEF Press Special, he visited many of the battlefields of France and Belgium.  He witnessed the Inter-allied Games in June 1919 and published a history of the games entitled History of the Inter-Allied Games Pershing Stadium, 1919.

     Returning to the US late in 1919, his mother joined him in Washington D.C. where he spent almost one year writing for General Pershing's staff for The Home Sector and The Independence.  Officially discharged from active duty, in 1920, he was promoted to Major of the Field Artillery Reserve. Late in 1920, he and his mother returned home to reside at Prospect Place where he resumed farming and his writing career.  A year following his mother’s death, in 1924, Joseph returned again to France and remained for seven months conducting extensive research for his book on SD in the World War.   

     In later years, deriving from his enthusiasm and expertise in military history, especially Civil War history, the National Park Service hired Joseph as Historical Assistant.  He compiled maps for battles at Petersburg, Antietam, Kennesaw Mountain, and Richmond.   He had a short stint as archeologist at Jamestown, from which he believed himself unqualified.  His final assignment with the National Park Service placed him as first superintendent of the newly established Manassas Battlefield Park in Virginia where he was instrumental in researching, mapping and designating historical signage and landmarks throughout the park.   

     In 1935, Joseph, along with 3 other Civil War enthusiasts from Manassas formed a group calling themselves the Battlefield Crackpates.  In 1952, the group formally organized and expanded into the Civil War Roundtable of Washington D.C.  Joseph was one of 18 as a founding member.  The Roundtable promotes the preservation of Civil War historical fields and landmarks.  Joseph and the members of the Roundtable actively lobbied and successfully prevented the federal government from building part of the interstate highway through the Manassas Battlefield.  In 1957, Joseph received the Roundtable’s Gold Medal Award for distinguished achievement in Civil War history.  One of the original Crackpates, artist Garnet Jex, painted Joseph’s portrait for the National Park Service at the Manassas Battlefield Park.  In 1953, Joseph’s last book, Bull Run Remembers, was published, compiled from his extensive research for the Manassas Battlefield Park. Joseph retired from the National Park Service in December 1947 and lived with his second wife, Rosamond, in Manassas until his death on February 11, 1960.  He is buried next to his parents in the Yankton Cemetery.

     In 1924, Joseph arranged for publication of a short work The Love Undending, a tribute to his parents.  It contains poetry written by JR, Annie and Joe and excerpts of a few letters exchanged between parents and son.  Other books to his credit include young readers' books such as With Sully into the Sioux Land, and The Trail to El Dorado.  Besides Bull Run his non-fiction military works include Pilot Knob, the Thermopylae of the West, The World War Through Stereoscope and most notably South Dakota in the World War, 1917-1919.  The South Dakota Historical Society commissioned the latter book, with funding appropriated by the State Legislature.