Trescowthick was involved in several Australian business enterprises.
With Norman Swann, Trescowthick founded Swann Insurance, which grew to be a major general insurer. Prior to being sold to CGU Insurance, Swann Insurance was Australia's largest privately owned general insurer.
Charles Davis Limited
Charles Davis grew under Trescowthick's leadership to become at one time Australia's fourth largest retailer, and third largest department store operator.
The company was renamed Harris Scarfe Holdings Limited in 1995.
Private business activities
In addition to his involvement in Charles Davis Limited, Trescowthick has been involved in several private ventures, including ownership of the Place Arcade in Toorak Village shopping centre in Melbourne Australia.
Community, Sporting and Charitable activities
Trescowthick has been involved in numerous community, sporting and charitable activities during his business career.
- He has supported the Geelong Football Club, and at one time was their No. 1 ticketholder.
- He has chaired Australian Olympic fundraising appeals.
- He supported the establishment of the Melbourne–Hobart yacht race.
- His support led to the establishment of the Sir Donald and Lady Trescowthick Centre for aged care in Prahran Victoria.
- He supported fundraising for construction of the tower for St Francis Xavier's Cathedral in Adelaide South Australia. (Harris Scarfe conducted fundraisers in its Rundle Mall department store).
Trescowthick was made a Knight Commander of the Order of the British Empire in 1979 and a Companion of the Order of Australia in 1991. He was inducted into the Sport Australia Hall of Fame in 1991 and received an Australian Sports Medal in 2000.
- Curriculum vitae
- Sir Donald and Lady Trescowthick Centre "Archived copy". Archived from the original on 11 April 2013. Retrieved 2012-09-07.
- "Trescowthick, Donald Henry, KBE". It's an Honour. Retrieved 23 December 2013.
- "Trescowthick, Donald Henry, AC". It's an Honour. Retrieved 23 December 2013.
- "Donald Trescowthick AC KBE". Sport Australia Hall of Fame. Retrieved 23 December 2013.
- "TRESCOWTHICK, Donald Henry: Australian Sports Medal". It's an Honour. Retrieved 23 December 2013.
- Harris Scarfe Holdings Limited 1995 Annual Report
- Harris Scarfe Holdings Limited 2000 Annual Report