Michael Lonsdale made his acting debut in the 1956 French historical comedy film ‘It Happened in Aden’ directed by Michel Boisrond. The film was inspired by Pierre Benoît’s 1940 novel, ‘The Environs of Aden.’ Following his debut, he went on to star in films like ‘La main chaude’ (1960), ‘Adorable Liar’ (1962), ‘Le Crime ne paie pas’ (1962), ‘The Trial’ (1962), ‘Behold a Pale Horse’ (1964), ‘Je vous salue, mafia!’ (1965), ‘Your Money or Your Life’ (1966), ‘Judoka-Secret Agent’ (1966), and ‘Les compagnons de la marguerite’ (1967). In 1968, he starred as ‘René Morane’ in the French film ‘The Bride Wore Black’ directed by François Truffaut. While the film opened to overwhelmingly negative reviews, it turned out to be a major box office hit and grossed over $9.6 million on a budget of $747,000. That same year, he also appeared in the French romantic comedy-drama film ‘Stolen Kisses’ directed by François Truffaut. The film was a critical and commercial success and went on to receive an ‘Academy Award’ nomination for ‘Best Foreign Film.’ He next starred in films ‘Hibernatus’ (1969), ‘Détruire, dit-elle’ (1969), ‘L'étalon’ (1970), ‘Le Souffle au cœur’ (1971), ‘Out 1’ (1971), ‘The Old Maid’ (1972), ‘The Day of the Jackal’ (1973), ‘Stavisky’ (1974), ‘The Phantom of Liberty’ (1974), ‘The Suspects’ (1974), ‘Galileo’ (1975), ‘Section spéciale’ (1975), ‘The Romantic Englishwoman’ (1975), ‘Mr. Klein’ (1976), ‘Bartleby’ (1976), ‘The Left-Handed Woman’ (1977), and ‘The Passage’ (1979).
In 1979, he portrayed ‘Hugo Drax’ in the spy-fi film and the eleventh installment in the James Bond series, ‘Moonraker’ directed by Lewis Gilbert. The film received a mixed response from critics but made big numbers at the box office, grossing over $210.3 million on a budget of $34 million. Lonsdale continued to star in films such as ‘Seuls’ (1980), ‘The Bunker’ (1981), ‘Chariots of Fire’ (1981), ‘Sweet Inquest on Violence’ (1982), ‘Enigma’ (1982), ‘Eréndira’ (1983), ‘The Judge’ (1984), ‘The Holcroft Covenant’ (1985), ‘Billy Ze Kick’ (1985), ‘The Name of the Rose’ (1986), ‘Der Madonna-Mann’ (1987), ‘Niezwykla podróz Baltazara Kobera’ (1988), ‘Souvenir’ (1989), ‘My Life Is Hell’ (1991), ‘The Remains of the Day’ (1993), ‘Jefferson in Paris’ (1995), ‘Nelly & Monsieur Arnaud’ (1995), ‘The Human Plant’ (1996), ‘Mauvais genre’ (1997), and ‘Don Juan’ (1998). He starred as ‘Jean-Pierre’ in the 1998 American action thriller film ‘Ronin’ directed by John Frankenheimer. The film received mostly positive reviews from critics and was a moderate financial success.
He next appeared in ‘A Monkey's Tale’ (1999), ‘Les Acteurs’ (2000), ‘Kaena: The Prophecy’ (2003), ‘Strange Crime’ (2004), ‘5x2’ (2004), ‘The Perfume of the Lady in Black’ (2005), ‘Munich’ (2005), ‘Goya's Ghosts’ (2006), ‘Heartbeat Detector’ (2007), ‘The Last Mistress’ (2007), ‘Agora’ (2009), ‘Of Gods and Men’ (2010), ‘Titeuf’ (2011), ‘Les hommes libres’ (2011), ‘Gebo et l'Ombre’ (2012), ‘Le renard jaune’ (2013), ‘Maestro’ (2014), ‘Les filles au Moyen Âge’ (2015), and ‘The First, the Last’ (2016). He was last seen in the 2016 sci-fi film ‘Sculpt’ directed by Loris Gréaud.