Theatre director, playwright and actor Peter Gill, who has died aged 86, has been described as a “gentle man with a fierce intelligence” who had a “quietly seismic” influence on British theatre.

Cardiff-born Gill performed with the Royal Shakespeare Company and appeared in films including HMS Defiant and Zulu before embarking on a successful theatre directing career.

Among those to pay tribute was Welsh actor Luke Evans, who credited Gill with launching his own career.

Gill’s agent Mel Kenyon said his work had a “rare emotional delicacy” that was “beautifully observed and finely tuned”.

Gill is closely associated with his work at the Royal Court in London, where he is credited with introducing the plays of English writer DH Lawrence to the theatrical world.

Born in Cardiff on 7 September 1939, he was raised in a working-class community and remained “fiercely proud of his Welsh heritage throughout his life”, according to an obituary written by his agency Casarotto Ramsay & Associates.

He pursued an acting career from the age of 18 before moving into theatre, most closely associated with the Royal Court, where he championed three Lawrence plays A Collier’s Friday Night, The Daughter-in-Law and The Widowing of Mrs Holroyd.

“Their success revived interest in Lawrence’s dramatic work and helped spark a renaissance of his plays in London theatre circles after decades of relative obscurity following his death in 1930,” the agency said.

He also presented two of his early plays, The Sleeper’s Den and Over Gardens Out, at the theatre, before becoming associate director in 1970.

In 1976, he became artistic director of Riverside Studios, with his production of William Shakespeare’s As You Like It marking the official opening of the Hammersmith-based theatre that year.

He also adapted Anton Chekhov’s The Cherry Orchard for the theatre, helping transform it from a “small fringe theatre” into a “venue regarded as the equal of the leading theatres of the West End”.

In 1980, he was appointed OBE for his services to theatre, also founding the National Theatre Studio in 1984 and running it until 1990.

Kenyon described Gill as a “gentle man with a fierce intelligence” and a “voracious reader” with an “expansive knowledge of the arts”.

“Whenever we talked, I walked away a wiser person. He taught me so much just by being him. He was a singular man, a kind, generous and curious man. I will miss him greatly,” Kenyon said.

Theatre director and producer Michael Grandage said he believed Gill’s contribution to British theatre “will come to be regarded as quietly seismic”.

“Through the observation of the domestic, he always gave us something universal,” he said, adding that future generations discovering his work would come across “some of the finest plays written in the last 70 years with unquestionably some of the most beautiful prose in the English language”.

Welsh actor Luke Evans also paid tribute to Gill in a post to Instagram, remembering the theatre director for changing the trajectory of his career after casting him in a 2008 revival of Small Change.

Over a black and white photo of the thespian, Evans – known for his roles in The Hobbit and Beauty and the Beast – wrote: “This man gave me a role in a play when I was 27 that changed my whole professional life.

“Peter Gill has passed away at 86 leaving behind a legacy of work that I was very lucky enough to be a small part of.

“Without that play Small Change that he wrote and directed me in, I don’t think I would have ever had a film career, or any career to be honest.

“RIP dear Peter and thank you.”

Tamara Harvey, co-artistic director of the Royal Shakespeare Company, said Gill was a “true artist and tirelessly devoted to the theatre”.

“His unerring ability to capture the complexity of human existence will live on in his writing but he will, nevertheless, be deeply missed,” she said.