[1] He started to work with Federico Fellini as artistic director on La Strada (1954) and Nights of Cabiria (1957).
[1] His most prized collaborations were on the film scripts of La Dolce Vita (1960), 8½ (1963), Juliet of the Spirits (1964), Orchestra Rehearsal (1978), and City of Women (1980), all co-written and directed by Fellini.
On the writing of La Dolce Vita, Rondi helped build up the character of Steiner, the intellectual who kills his wife and children.
In a letter dated October 1960, Fellini outlined his initial ideas to Rondi that were later developed into the screenplay with co-writers Ennio Flaiano and Tullio Pinelli.
[3] He made his directorial debut with Violent Life in 1961 based on the novel by Pier Paolo Pasolini.