Vitali was born Alfred Leon in 1948 in Leamington Spa, Warwickshire, England, and went on to attend London Academy of Music and Dramatic Art. Vitali guest-starred in a number of TV series in the early 1970s, appearing in Softly, Softly, Follyfoot, Roads to Freedom, Z Cars, Public Eye, The Fenn Street Gang, series 1, and Notorious Woman among others. In 1973, he made his feature film debut in two movies: the Italian Super Bitch, directed by Massimo Dallamano, who had previously worked with Sergio Leone as a Cinematographer in the first two of his Dollars Trilogy, and the television film Catholics, next to Martin Sheen and Michael Gambon.

It wasn't until 1975 that Vitali met Stanley Kubrick, with whom he would go on to have a professional relationship for the rest of Kubrick's career. Vitali answered a cast call for Barry Lyndon and got the part of Lord Bullingdon, the title character's stepson. Kubrick and Vitali bonded during the shoot. Five years later, Kubrick sent Vitali a copy of Stephen King's The Shining and asked him to join the production of Kubrick's next film, to which Vitali eagerly agreed. He is credited in The Shining (1980) as "personal assistant to director".

In 1977, he portrayed Victor Frankenstein in Terror of Frankenstein, Calvin Floyd's adaptation of Mary Shelley's classic Frankenstein, where he met his Future wife Kersti Vitali, who worked as costume designer in the shoot. The Vitalis then worked as costume designers in Birgitta Svensson's Mackan, after which Leon played a bit part in Svensson's next film, Inter Rail (1981). Leon and Kersti would divorce later on.

Vitali teamed with Kubrick again for Full Metal Jacket (1987), where he served both as casting Director and assistant to Director. Twelve years later, Vitali was credited with the same titles in working with Kubrick in what would be the director's last film, Eyes Wide Shut (1999), in which Vitali also played the Red Cloak; the words "fashion designer Leon Vitali" also appear in the third column of the newspaper article that Tom Cruise's character reads to learn about a former beauty queen's hotel drugs overdose.

In 1999, Vitali and filmmaker Todd Field, with whom he appeared in Eyes Wide Shut, began discussing the possibility of making films together. Vitali is credited as "technical consultant" on Field's In the Bedroom (2001), and as "associate producer" on Field's Little Children (2006), where he also made a cameo appearance as "The Oddly Familiar Man".

Since Kubrick's death, Vitali has overseen the restoration of both picture and sound elements for most of Kubrick's films. In 2004, Vitali was honored with the Cinema Audio Society's President's Award for this work.

He played the apothecary in Carlo Carlei's Romeo & Juliet (2013).

In 2017, Vitali was the subject of a documentary, Filmworker, directed by Tony Zierra and screened at the London Film Festival in October 2017, in which he is interviewed at length about his work with Kubrick.