Wiacek, 39, heads the human rights department at Warsaw University. He succeeds Adam Bodnar, who was unpopular with the government for raising issues with it and trying to block some of its decisions.
Bodnar's statutory term expired in September but he stayed on as no successor had been named. A ruling from Poland's Constitutional Court, where the government has placed many loyalists, ended Bodnar's interim status last week.
In his first statement after the Senate's approval, Wiacek described himself as an “independent” person who favors resolving the country's disputes with the European Union. Poland joined the EU in 2004.
He said he supports heeding a recent ruling by the European Court of Justice ordering Poland to immediately suspend the activity of a new body charged with disciplining judges and prosecutors. The EU and critics in Poland say the Disciplinary Chamber, based at the Polish Supreme Court, undermines judicial independence because many of the cases considered there are against judges who are critical of the government.
“I believe that the Disciplinary Chamber should suspend its activity. We should carry out the EU court's ruling as soon as possible,” Wiacek said.
But he also stressed that Poland's Constitution is the nation's supreme law. The Constitutional Court is expected to rule next month on whether the constitution takes precedence over EU treaties.
This story has been corrected to say that the Supreme Court's Disciplinary Chamber sanctions judges, not the parliament.