In 1995 Sheehy left STC to become Administrator of Sydney Festival (Sydney's international arts festival, and Australia's largest arts festival) under the leadership of Anthony Steel and in 1997 became Deputy Director to Steel's successor, Leo Schofield.
Sheehy completed four Sydney Festivals as Schofield's deputy (1998 to 2001) and succeeded Schofield as Festival Director and CEO in February 2001.


 
Sheehy's four Sydney Festivals (2002 to 2005) included 37 world premieres, saw the festival double its box office attendances, posted four successive financial surpluses, recorded a 30% increase in attendances to free outdoor events, established satellite festival precincts at Fox Studios Australia and in Greater Sydney, developed a following in the 18 to 35 age group, was voted Sydney's Best and Most Popular Event by the Sydney Chamber of Commerce, and was twice named the Best Event in New South Wales (2003 and 2005) by NSW Tourism (since renamed Destination NSW).

 
Some features of Sheehy's Sydney Festival programs included the first precinct-wide special effects lighting of historic buildings, titled Neon Colonial, which was later mirrored and extended by the Vivid Sydney festival; the curation of chamber music programs by guest composers Michael Berkeley (now Baron Berkeley of Knighton) and Brett Dean; large-scale outdoor visual art installations (including those by Michael Riley and Nam June Paik); outdoor concerts (including two concerts annually in Sydney's Domain, playing to audiences of between 70,000 and 100,000 each); expansive indoor and outdoor theatre performances including the Australian debuts of Théâtre du Soleil, Compagnia Di Valerio Festi, Les Arts Sauts (with Ian Scobie's Arts Projects Australia) and Transe Express, as well as Improbable theatre's Sticky and La Fura Dels Baus's OBS Macbeth; and the epic outdoor Indigenous productions Crying Baby and Eora Crossing.

Heiner Goebbels' Hashirigaki, Osvaldo Golijov's La Pasión según San Marcos, Sir Ian McKellen in Dance of Death, London Sinfonietta, Jon Lord's Concerto for Group and Orchestra, Asian Dub Foundation and the performance-poetry Broadway hit Def Poetry Jam also saw sell-out performances, along with the Festival's co-commission of the international production of The Black Rider by Tom Waits, Robert Wilson and William S. Burroughs, directed by Wilson.

Sheehy's final Sydney Festival event at the Sydney Opera House Concert Hall, the Came So Far For Beauty Leonard Cohen tribute concert starring Jarvis Cocker, Beth Orton, Nick Cave, Rufus Wainwright and Antony Hegarty among others, was filmed and recorded for the international documentary and album Leonard Cohen: I'm Your Man.

During Sheehy's Sydney Festival tenure, two of Sydney Festival's corporate partnerships received Australian Business Arts Foundation (ABAF) Awards including Australia's Corporate Partnership of the Year.
In 1995 Sheehy left STC to become Administrator of Sydney Festival (Sydney's international arts festival, and Australia's largest arts festival) under the leadership of Anthony Steel and in 1997 became Deputy Director to Steel's successor, Leo Schofield. Sheehy completed four Sydney Festivals as Schofield's deputy (1998 to 2001) and succeeded Schofield as Festival Director and CEO in February 2001.

 
Sheehy's four Sydney Festivals (2002 to 2005) included 37 world premieres, saw the festival double its box office attendances, posted four successive financial surpluses, recorded a 30% increase in attendances to free outdoor events, established satellite festival precincts at Fox Studios Australia and in Greater Sydney, developed a following in the 18 to 35 age group, was voted Sydney's Best and Most Popular Event by the Sydney Chamber of Commerce, and was twice named the Best Event in New South Wales (2003 and 2005) by NSW Tourism (since renamed Destination NSW).
 
Some features of Sheehy's Sydney Festival programs included the first precinct-wide special effects lighting of historic buildings, titled Neon Colonial, which was later mirrored and extended by the Vivid Sydney festival; the curation of chamber music programs by guest composers Michael Berkeley (now Baron Berkeley of Knighton) and Brett Dean; large-scale outdoor visual art installations (including those by Michael Riley and Nam June Paik); outdoor concerts (including two concerts annually in Sydney's Domain, playing to audiences of between 70,000 and 100,000 each); expansive indoor and outdoor theatre performances including the Australian debuts of Théâtre du Soleil, Compagnia Di Valerio Festi, Les Arts Sauts (with Ian Scobie's Arts Projects Australia) and Transe Express, as well as Improbable theatre's Sticky and La Fura Dels Baus's OBS Macbeth; and the epic outdoor Indigenous productions Crying Baby and Eora Crossing.
Heiner Goebbels' Hashirigaki, Osvaldo Golijov's La Pasión según San Marcos, Sir Ian McKellen in Dance of Death, London Sinfonietta, Jon Lord's Concerto for Group and Orchestra, Asian Dub Foundation and the performance-poetry Broadway hit Def Poetry Jam also saw sell-out performances, along with the Festival's co-commission of the international production of The Black Rider by Tom Waits, Robert Wilson and William S. Burroughs, directed by Wilson.
Sheehy's final Sydney Festival event at the Sydney Opera House Concert Hall, the Came So Far For Beauty Leonard Cohen tribute concert starring Jarvis Cocker, Beth Orton, Nick Cave, Rufus Wainwright and Antony Hegarty among others, was filmed and recorded for the international documentary and album Leonard Cohen: I'm Your Man.
During Sheehy's Sydney Festival tenure, two of Sydney Festival's corporate partnerships received Australian Business Arts Foundation (ABAF) Awards including Australia's Corporate Partnership of the Year.
Brett Sheehy