Lou is a London based theatre director who was the founding Artistic Director of the famous Gate Theatre, Notting Hill. His work established the Gate as an important theatre for the introduction of American and European drama to the British public. His adaptations there, such as DOWN AND OUT IN PARIS AND LONDON and MISS LONELYHEARTS were another cornerstone of the Gate’s pioneering policy. DOWN AND OUT IN PARIS AND LONDON, adapted from George Orwell by Lou, was subsequently produced at the Edinburgh Festival, where it was an award-winner.

He was also the Founding Artistic Director of The Gate at the Latchmere, Battersea. the sister theatre of the Gate, Notting Hill. The theatre quickly achieved a high profile, by combining the Gate's trademark policy of introducing undiscovered international classics and new works with a late night comedy series where performers and stand-up comedians such as Dawn French and Jennifer Saunders, Lenny Henry, John McCarthy, and Eric Begosian all started new shows off. A parallel policy at the Gate, Notting Hill saw the appearance of such performers as Hugh Grant, Pamela Stephenson, and John Sessions. The Gate at the Latchmere was the first London home of the Perrier Comedy Award. The opening production there "Fear and Loathing in Las Vegas" transferred to the Fortune Theatre in the West End. "No new theatre has opened with such a bang" said the Times. Before transferring, the production ran for a sell-out three months.

While Artistic Director of both Gate Theatres, The Observer's Peter Roberts wrote "He offers an unusual amalgam of stage direction, play adaptor and theatre administrator...he’s earned himself a reputation as a theatre man to be watched".

As Artistic Director of the Palace Theatre, Watford, he heightened its profile with important British and World premieres (for example he directed Edna O'Brien's version of MADAME BOVARY with Helen Mirren). Many West End transfers from Watford while he was Artistic Director there included A COMMON PURSUIT with Stephen Fry, John Gordon Sinclair and Rik Mayall, BUS STOP with Jerry Hall, and the game show musical SPIN OF THE WHEEL with Maria Friedman.

Tom Sutcliffe, in the Independent wrote "This continues Watford's remarkable renaissance under its director, Lou Stein". During his artistic directorship at Watford, he premiered thirty-three plays by living playwrights, including new versions of European classics by leading writers including Michael Frayn (The Seagull); Edna O'Brien (Madame Bovary) and Ranjit Bolt (The Marriage of Figaro and The Barber of Seville). Watford's reputation as a leading national repertory theatre soared during his time there, with many awards, West End transfers, and national tours.

Lou trained with the prestigious BBC's Television Drama Director’s Course, where he wrote and directed his own short film (Grey Panther). Recently, Lou has produced, directed, and written drama for BBC Radio, including his original play MY MONTH WITH CARMEN, his adaptation of writer Bernard MacLaverty's GRACE NOTES, starring Amanda Burton, and his adaptation of Sandor Marai's recent best-seller, EMBERS, starring Patrick Stewart.

He collaborated on a number of music theatre shows with leading contemporary composer Deirdre Gribbin. With Gribbin he has co-created and directed ACCORDING TO, based on the accordion music of Stravinsky, Piazzola, and Gribbin, which appeared at the National Concert Hall in Dublin and the Huddersfield Contemporary Music Festival. NOTES FROM THE EDGE featured Bernard MacLaverty's novel "Grace Notes", with live musicians, actors and premiered to acclaim at the Belfast International Festival. His 2005 music theatre spectacular THE VENUS BLAZING TOUR appeared at the South Bank Centre, London and toured to large national venues, including Warwick Concert Hall, The Liverpool Philharmonic Hall, and St. David's Concert Hall in Cardiff.

Lou established the Lou Stein Studio in 2022, working with neurodiverse actors and other professionals, building new ensemble skills using collaborative, non-judgemental and inclusive methods.