The pioneering documentary film-maker Robert Drew died on Wednesday, aged 90. Drew, a key figure in the development of “direct cinema”, the low-key observational style that nonetheless could produce gripping films, died at home in Sharon, Connecticut.

Drew was a former correspondent and editor at Life who wanted to reproduce the magazine’s famed photojournalism in moving-image form. He spent a year at Harvard researching why “documentaries are so dull, and what would it take for them to become gripping and exciting?” He met director Richard Leacock and was inspired to set up his own production company, Drew Associates, and along with Leacock and other young film-makers – including Albert Maysles and DA Pennebaker – set out on a mission to revolutionise the form.

Drew’s landmark production was a behind-the-scenes political documentary called Primary, in which he chronicled John F Kennedy’s presidential primary campaign in Wisconsin. It won a string of awards and put Drew – and direct cinema – on the map.

Drew oversaw a string of award-winning films in the 1960s, including Crisis: Behind a Presidential Commitment (1963), another JFK documentary about the clash over racial integration at the University of Alabama, and The Chair (1963), about a lawyer’s fight to save a convict from execution.

Drew’s wife Anne, who died in 2012, also produced a string of documentaries for Drew Associates, including Kathy’s Dance (1977), a film about dancer Kathy Posin, and Life and Death of Dynasty (1991), about India’s Nehru-Gandhi political family.

Drew’s work was hailed by Fahrenheit 9/11 director Michael Moore, who said: “Modern art has Picasso. Rock’n’roll has Bill Haley. And the documentary film has Robert Drew.”