Jim Roy, speaking for plaintiffs suing well owner BP Plc, drilling rig owner Transocean Ltd, cement services provider Halliburton Co and others, said BP executives at the highest level felt pressure to push output to the limit.
"Production over protection. Profits over safety," Mr Roy said.
He was the first of many lawyers scheduled to speak during yesterday's opening statements in the non-jury trial before US District Judge Carl Barbier.
The first phase of the trial is focused on how much each company is to blame for the disaster and the degree of negligence.
Most observers expect the case to be settled before it goes to a verdict.
"BP is in a very tight bind. I never thought they intended to try this case and they really cannot afford to do so because the exposure is potentially too catastrophic," said Blaine LeCesne, a professor at Loyola University College of Law in New Orleans.
Lined up against the defendants are the US Justice Department, several Gulf Coast states, and plaintiffs represented by Mr Roy that did not take part in an $8.5 billion (£5.6bn) settlement that BP struck last year.