Travis Banton started designing costume for Paramount Pictures in 1924, following a successful career as a mainstream clothes designer in New York. Banton's career change from clothing designer to becoming the Head of the costume department at Paramount came when Mary Pickford chose him to design her wedding dress for her marriage to Douglas Fairbanks. It was in the 1930s that Banton reached the pinnacle of his career dressing top actresses, including Bebe Daniels, Clara Bow and Evelyn Brent. Banton first worked with Marlene Dietrich on Morocco and afterwards Dietrich personally chose Banton to design her costumes until his departure from Paramount Studios in 1938. While filming Morocco, Dietrich wrote the designer, Travis Banton, is talented. Jo [Sternberg] tells us what he wants and Travis and I discuss what the clothes should be. Edith Head biographer Paddy Calistro explains that Banton spared nothing in dressing Dietrich. She was the femme fatale, and he used his couturier flair to define her character.

After 'discovering' Dietrich in The Blue Angel, 1930, Sternberg encouraged her to move to the U.S. under contract with Paramount. Morocco was their first collaboration and introduced the star to an American audience. In his biography of Dietrich, Steven Bach states that the entire first third of the picture is devoted to nothing but the creation of a star. Sternberg's unveiling of Marlene Dietrich may be the most memorable star introduction in movie history. Just arrived in Morocco to work at a local cabaret club, we see Amy Jolly [Dietrich] backstage dressing in her top hat and tails. She then takes to the stage, nonchalantly taking in the scene of the hostile crowd, cigarette smouldering. Her performance of Quand l'amour meurt wins over the crowd, and she follows the song with what Bach names the most memorable enunciation of sexual ambiguity in any picture - she takes a flower from a lady and kisses her full on the mouth, then tosses the flower to a Legionnaire. Bach states It is one of the great defining moments in film history, and contemporary reviewers understood it as... a signal that the woman who "won't need any help" is prepared to take on a man's world in a man's uniform with a man's daring. The top hat and tails are her armour and warning, the flower her invitation and challenge. Dietrich looks like indifference, but she's just levelling the field.

Dietrich's own style was the inspiration for the costume - she wrote tomorrow we start work on the costumes. One of them will be my own top hat, white tie, and tails that Jo saw me wear in Berlin at that party. When Sternberg and Dietrich filmed a short introductory scene in the costume, Dietrich wrote that the Studio roof blew off. "Slacks" are not worn by women in America. The feeling is that no man looks at a woman in trousers. She admitted that the reason I wore tails in Morocco was because Jo wanted to hide the legs, and I looked wonderful in them, and the Americans would be shocked!

Dietrich received her only Oscar nomination for her performance in Morocco.