He studied in Florence where his family had settled, here he entered in a competition for young players, in which he won a stay of three days to Cinecittà and a modest role in a film by Nino Taranto.
After this, he moved to Rome and the world of cinema where he worked in small parts in about 18 films.
In 1958, with Domenico Modugno, Migliacci coauthored the song Nel Blu Dipinto Di Blu, aka Volare, which has become one of the most well-known Italian songs in the world. While the words of the title, "in the blue, painted blue," seem to make no sense, they actually do when one understands the inspiration for the song came out of a wine fueled vision of Franco's combining his memory of two Marc Chagall paintings and himself painted blue with the ability to fly.
Afterward, he worked in drama series for television and several radio plays. He was then the illustrator for The Pioneer children's magazine directed by Gianni Rodari.