Trinity (Terence Hill) is a cowboy who keeps himself afloat with little scams. At the beginning, for example, he "takes over" a prisoner from the hands of two bounty hunters, who also experience at first hand why Trinity is also called "the right hand of the devil". With the Mexican prisoner, Trinity rides to the next town and arrives in the moment, when his brother Bambino (Bud Spencer), who is actually a horse thief but has now found a hideaway as sheriff, finds himself facing three bandits in a duel. While the prisoner is already saying a prayer for the sheriff, Trinity doesn't even think about helping his brother, because unlike the three pitiful pistoleros, Trinity knows that his brother is also called "the devil's left hand" and so he is convinced that his brother will kill the three bandits if they really try to shoot him. That's how it happens. Following the duel, it turns out that the three bandits were part of the people of the major, who have the city firmly under their control and set themselves the goal of driving a few peaceful settlers out of a nearby valley. Bambino doesn't like this, because he is worried that a bloodbath among the settlers would alarm the rangers and then his life as wrong sheriff would be over. He can't risk that, because he waits in the city for two comrades with whom he wants to help the major around his herd of cattle. Bambino persuades Trinity to stay and support him in the fight against the Major and his men and appoints him as his deputy sheriff. Together, they now not only record it with the Major, but also with the Mexican bandit Mescal and his gang, who occasionally cross the border to harass the settlers and who later form an alliance with the Major against the settlers. After various small skirmishes, the showdown finally takes place in the valley of the settlers.
With "They call me Trinity", the duo Bud Spencer and Terence Hill achieved their first major success. Thus, this film was the actual starting signal for the successful joint film career, even though it was the fourth time that she had appeared together as the main actor in front of the camera after God forgives, I don't, Ace High und Boot Hill (they were also in Hannibal in 1959, but only in supporting roles there).
"They call me Trinity" was the first serious attempt to add humour to the serious and increasingly brutal Italo-Western. The screenwriter and director Enzo Barboni hit the nerve of time. However, many producers were not convinced of the movie's success beforehand, which is why Barboni had to do a lot of work with his screenplay before he found a producer in Italo Zingarelli who was convinced by his revolutionary idea of western comedy.
Director Enzo Barboni has worked as a cinematographer for many years and in this job he also met Terence Hill and Bud Spencer before. He was cameraman for Little Rita of the West, Viva Django und The Five Man Army. In 1966 he celebrated his greatest success as a cameraman with "Django", the original movie with Franco Nero. "They call me Trinity" was Carbonis second directing. One year earlier he made his debut with the conventional Italo Western "The Unholy Four" (Ciakmull, l' uomo della vendetta). For this film he has already acquired his pseudonym E. B. Clucher. Until 1990 Barboni made eight more films with Bud Spencer and / or Terence Hill, which all had a decisive influence on the image of the duo.
With "They call me Trinity" the Spencer/Hill duo also created their future trademark, the extensive brawl. The two had smaller skirmishes in Ace High and Spencer also in Boot Hill, but the perfectly shaped brawl in the well-known form celebrated its premiere here.
The brawls were choreographed by Giorgio Ubaldi, who had a firm ensemble of stuntmen. These stuntmen also became an integral part of the Spencer/Hill movies.
Permanent villain Riccardo Pizzuti also had his first memorable appearance here in the role of Jeff. From then he was also part of the regular cast in many of the duo's other films.
In one scene of the film, Terence Hill has a baby of the Mormons on his arm and tickles them with his Colt. The baby is his own son Jess.
The striking title song of the film was written by Franco Micalizzi and is whistled by Alessandro Alessandroni, whose whistles have also enriched many of Ennio Morricone's soundtracks, including the one of "Once upon a time in the West". Many years later Quentin Tarantino used the title song for the end scene of his western "Django Unchained".