Studio publicity material credited René Cardona as co-director and Jorge Stahl Jr. as Lucien Ballard's camera operator, but it is unknown if they ever worked on this picture and likely that they had been only hired to make sure union requirements were fulfilled.
The Spanish infantry are wearing 17th century motion helmets. Those helmets were out of fashion long before 1769, the year this film takes place.
The real Fr Junipero Serra was beatified (called "blessed") by the Catholic Church some years ago, which is the first step towards sainthood. He is now referred to as Blessed Junipero Serra.
The working title of this film was The Gun and the Cross. In a spoken foreword, the film announces that only "one language" would be used in the dialogue, despite the varying ethnic backgrounds of the characters. In the onscreen credits, actor Julio Villarreal's surname is incorrectly spelled "Villareal."
According to an Aug 1954 HR news item, Edward Dmytryk was originally assigned to direct the picture. According to an 18 Jan 1955 HR news item, Cameron Mitchell had been cast in a lead role, and in Feb 1955, HR announced that singer Russell Evans was considered for a part in the picture. HR news items include Felipe Méndez, Jan Svelk, Jaime Del Rosario, Jack Maner and Gilda Fontaine in the cast, but their appearance in the completed picture has not been confirmed. A 4 Apr 1955 HR news item stated that the "famous choir" of Franciscan Cathedral Toluca, a four-hundred-year-old church near Mexico City, was going to be used in the film for "special choral effects," but the choir's participation in the released picture has not been confirmed.
Seven Cities of Gold was mostly filmed in Mexico, in and around the west coast town of Manzanillo and the deserts of Guadalajara. An Indian village was built as a set in the hills near Manzanillo, and a reproduction of the original San Diego mission was constructed on the beach. Although studio publicity material credits Mexican director/producer René Cardona as Robert Webb's co-director, and Mexican director of photography Jorge Stahl as Lucien Ballard's camera operator, it is likely that they were hired only to fulfill union requirements and did not actually work on the production. A few sequences of the picture were shot on location in Topanga Canyon, CA, according to a 19 May 1955 HR news item.
As depicted in the film, in 1769, Padre Junípero Serra (1713--1784) accompanied the expedition of José de Galvez to Upper California and founded the Mission San Diego de Alcala. It was the first of twenty-one Franciscan missions established in California. On 25 Sep 1988, Serra was beatified, the first step leading to sainthood in the Catholic Church. The MPH reviewer remarked that Seven Cities of Gold was the "first important film dealing with" Serra's contributions, while the HR review commented that it was "the first film to pay attention to the important contributions of culture and humanity made by the Spanish to the development of more than half of the new world." Director-producer Webb and producer Barbara McLean were married at the time of this production. Seven Cities of Gold marked the first producer assignment of longtime Fox film editor McLean.
(AFI Catalog).