In Spike Jonze's "Her," Johansson played the voice of a seductive computer operating system that attracts the amorous desires of the film's protagonist, played by Joaquin Phoenix.
McConaughey was honored for his work in Jean-Marc Vallee's "Dallas Buyers Club," which also won the festival's audience award.
The award to "Tir" means the last two major Italian film festivals honored Italian-made documentaries with their top awards, following the Venice Film Festival, which in September gave its top prize to "Sacro GRA" from Gianfranco Rosi. Before that, no documentary had ever won the top award at either of the festivals.
Among the other sections, Aliona Polunina won the CinemaXXI section for innovations in cinema with "Nepal Forever," while Scott Cooper won the prize for best first or second film for "Out of the Furnace," part of the main selection. "Dal profondo" from Valentina Pedicini won the award for best Italian documentary.
Festival officials said that early indications were that the event out-performed last year's event in every aspect, with ticket sales 20 percent higher and the average film screening to cinemas 70 percent full. An estimated 150,000 people attended the events over 10 days, with high media attention, including more than 750 reports in the international press, nearly 1,200 in the national printed press, and an average of more than 500 articles a day online over the length of the festival.
The Business Street, the festival's market event, also saw increases, with representatives of 49 countries on hand and 10 percent more badge holders and 15 percent more buyers than a year ago.
Earlier in the day, Muller said the Rome event would become a "festaval" -- a term he coined from a mix for the Italian words for "festival" and for "party," meaning it would be a hybrid event with characteristics of both types of events.