Glen Cayley, head of Shell UK's upstream exploration and production business, has been appointed vice chairman of the industry body.
Mr Cayley will represent the community of operators, which own and run oil and gas fields.
Colette Cohen, senior vice-president for the UK and the Netherlands for the exploration and production arm of Centrica, which owns Scottish Gas, has joined Oil & Gas UK's executive board.
Malcolm Webb, chief executive of Oil & Gas UK, described Mr Cayley and Ms Cohen as high-calibre representatives of the operator community.
He said: "We need to see some real change if we are to maximise economic recovery (of oil and gas). Whilst current capital expenditure is at all-time high, exploration levels are low, average productivity has fallen and our cost base is increasing.
"The next chapter for our industry will certainly be different from the past and could well be more difficult. However, by working collaboratively across the industry and governments, I believe we can work towards a sustainable future. Oil & Gas UK and its board of directors have a vital role to play in all of this. It is encouraging, therefore, to see our board further strengthened by these appointments."
Mr Cayley became head of Shell's North Sea business in 2010. He worked at Exxon for over 25 years.
Ms Cohen has run Centrica's North Sea business since August, after spending 20 years at ConocoPhillips.