Born in Zielenzig in 1944, a few weeks before the arrival of the Red Army, Lommel’s family fled the city, wrapping the infant Ulli in a roll of carpet. His father, Ludwig, was a popular radio personality. His mother was the actress Karla van Cleef.

Lommel started his cinematic career as an actor in the early 1960s. One of his first film roles was in Russ Meyer’s Fanny Hill, in which he starred alongside Italian actress Letícia Román. In 1969, he appeared in Rainer Werner Fassbinder’s directorial debut Love Is Colder Than Death. The movie, an existentialist, film noir, received a shocked and confused response at the Berlin International Film Festival in 1969, but the cast as an ensemble would go on to win an award at the German Film Awards in 1970.

In 1971, Fassbinder’s surrealist western Whitey, which Lommel produced and starred in the leading role, won several German Film Awards (the German Oscars). Shot in Almeria, Spain, in the summer of 1970, the shoot was so tumultuous and grueling that it became the source of inspiration for the subsequent Fassbinder film, Beware of a Holy Whore. Beware of a Holy Whore was a postmodern analysis of Fassbinder’s career. in which he used fourth wall methods to poke fun at the trials and tribulations of filmmaking.

Lommel moved to the United States in 1977 and started working with Andy Warhol. He became fascinated with Warhol’s artistic style. Lommel owned an array of Warhol’s polaroid photographs and pop art pieces. Their friendship led to Warhol becoming involved with several of Lommel’s films. He produced Cocaine Cowboys, a rock and roll western which starred Jack Palance. Warhol appeared in Lommel’s Blank Generation (1978), a film which focused on the punk rock scene in New York City. It starred the punk icon Richard Hell and his band Richard Hell and the Voidoids. Several scenes were filmed in CBGB and offer an insight into the frenetic madness of the scene at the time.

In 1980, Lommel directed The Boogeyman (1980) which became a worldwide hit. The film gained notoriety in the UK, when it was added to the DPP ‘Video Nasties’ list. After the success of Boogeyman, Lommel made several more genre features, including Brainwaves [it] (1983), starring Tony Curtis and Vera Miles, The Devonsville Terror (1983) with Donald Pleasence, and Revenge of the Stolen Stars (1985) with Klaus Kinski.

In 2002, Lommel participated in the documentary Fassbinder in Hollywood, which is available as part of the Arrow Films and Video Fassbinder Collection (Vol 2). The documentary contains an interview with Wim Wenders.

In 2016, Hollywood Action House began developing Boogeyman Chronicles, a series of eight 45-minute episodes. Inspired by Lommel’s 1980 cult hit The Boogeyman, the first episode was planned to begin airing worldwide on Halloween 2018. The new story line was developed after test audiences in the U.S. and Europe saw various cuts of a series of plot-possibilities and characters titled “Boogeyman Reincarnation”. The writing team headed by Colin McCracken worked on episodes 2-8 with the plan to create a total of up to 64 episodes. Lommel indicated that, even though he directed episode 1, most of the remaining episodes would be directed by a series of young directors from the U.S, Europe and Asia.