[4] Williams first joined Sydney Theatre Company (STC) in 2012, when he was appointed Directing Associate by then Artistic Directors Cate Blanchett and Andrew Upton.
In 2014, for Sydney Theatre Company he directed productions of Macbeth starring Hugo Weaving and Maxim Gorky's Children of the Sun adapted by Andrew Upton.
In 2016, for STC Williams directed a revival of the Australian classic The Golden Age by Louis Nowra, Shakespeare's A Midsummer Night's Dream, and Arthur Miller's All My Sons, for which he was nominated for Best Director at the Sydney Theatre Awards.
The highly acclaimed production brought to life Ruth Park's celebrated trilogy of novels, Missus, The Harp in the South, and Poor Man's Orange, using an ensemble of 18 actors to perform the marathon work across two nights of theatre.
Williams finished 2018 with an operatic take on Patrick White's classic play A Cheery Soul, featuring his signature use of live video.
Staged at the Sydney Opera House, the production starred Sarah Peirse, with an ensemble including Anita Hegh, Shari Sebbens, and Tara Morice.
Starring Mia Wasikowska as Ralph, the production featured an ensemble including Joseph Althouse, Justin Amankwa, Nyx Calder, Yerin Ha, Daniel Monks, Mark Paguio, Rahel Romahn, Eliza Scanlen, Contessa Treffone, and Nikita Waldron.
The one-person show saw actor Eryn Jean Norvill play 26 characters in a two-hour performance at the Roslyn Packer Theatre that incorporated Williams' signature use of live video.
[12] In 2021 Williams reunited with playwright Kate Mulvany to direct her adaptation of Ruth Park's cult classic Playing Beatie Bow.
Time Out praised the work as bringing "Shakespeare's revered classic right up to the very minute", while The Guardian declared Williams a "technological innovator in theatre".
[30] In addition to the national tour of Dorian Gray, 2022 saw Williams write and direct an acclaimed adaptation of Robert Louis Stevenson's Strange Case of Dr Jekyll and Mr Hyde.
The production, featuring an ensemble including Guy Simon, Mandy McElhinney, Shiv Palekar, Claude Scott-Mitchell, Megan Wilding, and Susie Youssef, was designed by Jake Nash and was praised by The Guardian for its "outstanding" performances and "revolutionary approach" to the script, which interpolated texts from other Shakespeare works including Richard II, Pericles, The Merchant of Venice, and Hamlet in order to amplify the voices of Caliban and Miranda.
[35] The London season of The Picture of Dorian Gray, starring Sarah Snook, premiered at the Theatre Royal Haymarket in February 2024 to critical acclaim.
[36] Williams has directed extensively for Sydney Chamber Opera (SCO) since 2011, including productions of Peter Maxwell Davies's The Lighthouse, Fausto Romitelli's An Index of Metals, and stagings of J. S. Bach's cantata Ich habe genug and Jack Symmonds' Nunc dimittis.
Williams was set to direct Handel's Hercules for English National Opera in the autumn of 2020, but the production was unable to proceed due to the Coronavirus pandemic.