In 1969 he wrote the initial direct debit and direct credit applications which are in common use throughout the New Zealand banking industry today, and by age 22 he was Head of Computer Programming at the Comalco aluminium smelter in Bluff, which at that time was the largest industrial project ever undertaken in New Zealand.
He returned to Christchurch around 1972, making it his home permanently. He lived in Jeddah, Saudi Arabia, working as a programmer for Caterpillar Inc. between 1976 and 1978, after which he returned to New Zealand to develop a new concept in computer programming through his creation of the fourth generation language known as LINC. LINC remains New Zealand's most successful software export to date. He has resided in Christchurch for the past 30 years, where there is now a street named after him, Sir Gil Simpson Drive.
Sir Gil is the founder of the Aoraki Corporation, developers of the LINC 4GL and Jade programming language, and Jade Software Corporation , who are also well known for their past sponsorship of Christchurch's Jade Stadium. His latest venture is Jolly Good Software Pty Ltd, which he founded in 2006 and manages from the Jolly Good gallery in Christchurch .
Honours and awards
In the New Year Honours 2000 Simpson was appointed a Knight Companion of The New Zealand Order of Merit for services to information technology, commerce and the community'. Later in 2000 Simpson was made an honorary fellow of the New Zealand Computer Society’s Supreme Award for the most outstanding contribution to computing in New Zealand in the 20th century. In 2005 he was inaugurated into the New Zealand Business Hall of Fame, an honour reserved for business leaders responsible for outstanding contributions to the nation. Sir Gil has also been a director on the board of the Reserve Bank of New Zealand, as well as that of numerous other companies, both public and private.
With many outstanding achievements his profile in information technology has accorded him:
- An honorary doctorate from the University of Canterbury, D.Sc (h.c.)
- Past presidency of the Royal Society of New Zealand, of which he is now an honorary member
- Chairman of the New Zealand government's E-Commerce Action Team 
- Chair of the New Zealand E-Commerce Summit, 2000 
- Chairman of the Christchurch City Mission
- Associate membership of the New Zealand Business Roundtable 
- Fellow of the New Zealand Institute of Management , and past membership on the NZIM advisory board
- Fellow of the New Zealand Institute of Directors 
- Honorary Fellow of the Institute of IT Professionals
- Founding patron of the Royal District Nursing Service, Australia 
- "The New Year Honours 2000" (19 January 2000) 3 New Zealand Gazette 93.
- "Honorary Fellows of the IITP (HFIITP)". About the IITP. Institute of IT Professionals of New Zealand. Retrieved 25 April 2013.
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- "Sorry, the page you’re looking for is not here". Rbnz.govt.nz. Retrieved 2013-10-15.
- "Home « Royal Society of New Zealand". Rsnz.org. 2013-10-11. Retrieved 2013-10-15.
- "E-commerce summit attracts huge interest". beehive.govt.nz. 2000-08-16. Retrieved 2013-10-15.
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