Frank Marshall wrote, directed, produced, edited, and sometimes acted in his witty and humorous films. He even built and designed his own sets and props. During the war he made instructional films on training women for war work (on the treatment of burns injuries) and The Life Saving Bank, to publicise the Blood Transfusion Service. Marshall was elected first chairman of the Scottish Association of Amateur Cinematographers, formed in 1949. During his lifetime he produced over 120 films of different genres, achieving frequent national and international success at amateur film festivals. He served on the board of the Scottish Film Council until 1972.