Boetticher's films through "The Killer Is Loose" (1956) exhibited a workman-like efficiency, the product of an intelligent man learning his job, but he upped the ante considerably when he embarked on a remarkable series of seven spare but stylish Westerns starring Randolph Scott, none longer than 78 minutes, on which his reputation rests. Beginning with "Seven Men From Now" (1956), Boetticher was the consummate auteur, assembling compatible talent to help him frame his vision with speed, economy and exhilaration. His formula pitted the strong-willed mythic hero (Scott) against an equally strong-minded gentleman-villain, the memorable interplay between the two frequently the product of witty scripts by Burt Kennedy, who collaborated on four of the seven pictures. Daring to give hero and villain equal prominence in his compositions and cutting patterns, Boetticher created an arena where fine actors like Lee Marvin, Richard Boone, Pernell Roberts, Claude Akins and James Coburn could shine opposite Scott, depicting a struggle between good and evil that was not simply a black-and-white affair. Though the delicate balance of power ultimately swings Scott's way, the viewer sees how elements outside man's control can influence the struggle and make clear-cut conclusions impossible.
Harry Joe Brown joined the Boetticher posse as producer of "The Tall T" (1957), serving in that capacity throughout the remainder of the series, and the film also marked the first of three outings with Charles 'Buddy' Lawton Jr. as director of photography. Boetticher shot many of these films around Lone Pine, California, its arid, barren landscape accentuating the isolated harsh world in which his characters dwelled. In addition to Lawton, he employed such gifted cameramen as William A. Fraker and Lucien Ballard (his cinematographer for the long-term "Arruza" documentary) to ensure the beautiful look of his pictures. Mentioned in the same breath as Ford and Anthony Mann, he made an art of the low-budget Western, and established the austere image of Scott alongside that of John Wayne as a preeminent hero of the genre. After "Comanche Station" signaled the end of the series, he added a fine gangster film, "The Rise and Fall of Legs Diamond" (both 1960), to his oeuvre before focusing his attention completely on his Mexican project.
Boetticher spent most of the next seven years south of the border pursuing his obsession, the documentary of his friend, the bullfighter Carlos Arruza, turning down profitable Hollywood offers and suffering humiliation and despair to stay with the project, including sickness, bankruptcy and confinement in both jail and asylum. Finally released in the USA in 1971, "Arruza" stands as a rich, fascinating portrait of a great athlete and man, containing spectacular photography of action so authentic and accurate that one can almost smell and breathe the dust, taste the blood. The rest of Boetticher's output since 1960 consists of the barely seen "A Time for Dying" (a collaboration with Audie Murphy released in 1971), the story for Don Siegel's "Two Mules for Sister Sara" (1970), the documentary "My Kingdom For..." (1985) and his appearance as a judge in Robert Towne's "Tequila Sunrise" (1988), but he is still actively attempting to get his screenplay "A Horse for Mr. Barnum" made, despite his advanced age.