Carlson received his Ph.D. in 1973 from Texas Tech, taught at Texas Lutheran College in Seguin in Guadalupe County, and returned to Tech in the early 1980s as a professor of history. He retired from the university in 2009. He has also been active throughout his career as a fellow of both the West Texas Historical Association, based at Texas Tech, and the Texas State Historical Association, headquartered at the University of North Texas in Denton. Carlson concentrates on ranching, frontier life, the military, and Indian affairs. He has through 2010 published 18 books and more than 200 articles, essays, and book reviews.
In 2006, Carlson edited The Cowboy Way: An Explanation of History and Culture, published by the Texas Tech University Press. Carlson wrote two chapters, "Myth and the Modern Cowboy" and "Cowboys and Sheepherders." In the preface, Carlson writes that the interest in the cowboys comes from:
dime novels and Buffalo Bill's Wild West Exhibition, then in the enormous popularity of Owen Wister's The Virginian (1902), and subsequently in the success of popular western novels of the type by Zane Grey and Max Brand, in western films (made in Italy, Germany, Hollywood, and elsewhere), in television programs in public television documentaries, and in other formats, including the highly effective use of cowboys as advertising symbols. Serious scholars—including historians, sociologists, literary critics, and others—have studied cowboys and the symbols and myths that surround them.
In the popular view cowboys were men on horseback. In fact, most of the time they spent their days on foot working at such farm-related chores as repairing fences and cutting hay. Even in Wister’s defining cowboy novel, for example, the hero of the story—the prototypal cowboy—herded neither cows nor cattle of any kind.
Other chapters of The Cowboy Way are "Cowboy Humor" by Kenneth W. Davis, "Stockyards Cowboys" by J'Nell L. Pate, "English Cowboy: The Earl of Aylesford in the American West," by James Irving Fenton (1932–2011) of Lubbock, "Cowboy Songs" by Robert G. Weiner, and "Vaqueros in the Western Cattle Industry" by Jorge Iber.
"Pecos Bill," a Military Biography of William R. Shafter, (Texas A&M University Press, 1989), is a study of a controversial military officer who was stationed for a time in West Texas. The officer is of course unrelated to the western character Pecos Bill, a creation of folklore. Carlson seeks to set the historical record straight in regard to General William Shafter, formerly considered a "fat, incompetent buffoon" who headed the American Expeditionary Force to Cuba in 1898. Much of the success of the AEF has been attributed to future U.S. President Theodore Roosevelt and his friend, General Leonard Wood.
After the American Civil War, Shafter returned to his native Michigan but found that he preferred military to civilian life. In 1867, he received a commission in the regular Army and was sent to Texas as a lieutenant colonel of the 41st Infantry, an African American regiment. Carlson describes Shafter's Texas sojourn as service "with distinction." Thereafter, Shafter fought in several Indian campaigns throughout the West. He was involved in peace restoration at Pine Ridge, South Dakota, in the wake of the 1890 massacre at Wounded Knee.
In the Spanish American War, Shafter transported a force of 16,000 men some 1,200 miles by water, and within ten days of landing drove back the enemy to his last line of defense at Santiago de Cuba. Within another two weeks, the city surrendered, and a Spanish army of 24,000 laid down its arms. Carlson concludes that Shafter's work in Cuba was certainly not that of a "buffoon."
According to the reviewer Roger D. Launius, Carlson:
corrects such misconceptions and rescues Shafter from ill consideration and obscurity. [His] portrait of William R. Shafter, therefore, is a refreshing revisionist analysis of an important nineteenth century military figure. Perhaps at times the author is too persistent in trying to rescue Shafter from his reputation as an incompetent, but the arguments he makes are compelling. Even so, Carlson, does not paper over flaws in his character. Shafter was obstinate, profane, a womanizer, a sometimes drunk, and single-mindedly hard-boiled. He was also, Carlson admits, energetic, ambitious, self-reliant, and hard-working. When one finishes this book, there is a sense that Shafter was a flawed but capable figure. 'Pecos Bill' is a fine book, well worth the reading.
With Tom Crum, Carlson published in 2010 Myth, Memory, and Massacre: The Pease River Capture of Cynthia Ann Parker. Cynthia Ann Parker was the mother of Comanche chief Quanah Parker, and had been taken captive in 1836, when she was a young girl. In 1860, she was taken prisoner in a raid on the Pease River by a contingent of Texas Rangers, led by Sul Ross, and United States cavalry. Carlson and Crum re-examine the plight of Parker and reveal a century of historical falsifications that have made the facts of the case a continuing mystery.
In 2006, Carlson also published Amarillo: The Story of a Western Town, a history of Amarillo, largest city in the Texas Panhandle.
In 2005, Texas Tech Press published Carlson's short volume of history and archaeology of the Llano Estacado, entitled Deep Time and the Texas High Plains: History and Geology. A reviewer write that early inhabitants of the Plains who came to the Lubbock Lake Landmark in the long Yellow House Draw, "camped, hunted game, and sought shelter from harsh winter weather." Carlson surveys the geologic past of the area, with emphasis on "human activity in the region . . . how early peoples adapted to shifting environmental conditions and changing animal resources. . . . Carlson places this significant national archaeological site in broad perspective, connecting it to geology and history in the larger upper Brazos River drainage system and, by extension, the central Llano Estacado. . . . "
The Plains Indians (College Station, Texas: Texas A&M University Press) won the History Book Club selection of 1998 and was subsequently published in 2004 in a French language translation in Paris. In 2005, The Plains Indians was named one of the 100 most outstanding books on the American West published in the 20th century.
Empire Builder in the Texas Panhandle: William Henry Bush (1849-1931), Texas A&M University Press, 1996, is the story of a versatile entrepreneur who made a fortune in many enterprises, including the Panhandle cattle industry.
Texas Woollybacks: The Range Sheep and Goat Industry (Texas A&M University Press, 1982) is a study of the sheep and goat industries in West Texas.
With the historians Donald R. Abbe (born 1949) and David J. Murrah (born 1941), Carlson co-authored Lubbock and the South Plains. In the 2014 West Texas Historical Review, Carlson published "The Nicolett Hotel and the Founding of Lubbock", a study based in part on the hotel register of the former landmark Nicolett Hotel in Lubbock.
In 2000, Carlson garnered the "Outstanding Researcher Award" from the Texas Tech College of Arts and Sciences. He served on the advisory committees for the Handbook of Texas, a creation of the Texas State Historical Association. He has worked on the Charles Goodnight papers. In 1993, he received the Texas Tech "President's Excellence in Teaching Award." In 2005, he was named outstanding professor by the Residence Life students. He has been twice named the "outstanding faculty member" of the Texas Tech history department. He has also been a director of the Texas Tech Center for the Southwest. In 2006, Carlson was elected to membership in the Philosophical Society of Texas.
On April 11, 2015, the West Texas Historical Association at its annual meeting this year at Amarillo College in Amarillo honored Carlson with the presentation "A Prof's Prof: A Timely Tribute to Paul Howard Carlson and His Versatile Body of Work." Susan Dickey of Jackson, Mississippi, discussed Carlson as "Young Teacher and Military Historian"; Leland Turner of Midwestern State University in Wichita Falls, presented "Carlson: Ranching Historian", and Scott Sosebee of Stephen F. Austin State University in Nacogdoches, Texas, concluded with Carlson as "Native American Historian."
Carlson and his wife, the former Ellen J. Opperman (born ca. 1941), reside in scenic Ransom Canyon in Lubbock County. There are two Carlson sons, Steven Y. Carlson (born ca. 1966) of Schertz, Texas, and Kevin A. Carlson (born 1971) of Ransom Canyon, and one daughter, Diane K. McLaurin of Lubbock.