In her speech, Justice Loukas-Karlsson paid tribute to the "magnificent role models" of female judges before her, as well as the lawyers who had supported her throughout her career. She said she was proud to be joining a court with such an "impressive reputation" and that she looked forward to the role in the ACT, "this most educated, progressive and civilised of places."

The ceremony heard that Justice Loukas-Karlsson was educated in Queensland and NSW, and practiced as a barrister primarily in NSW. But she is also no stranger to Canberra, having appeared before as counsel in the High Court of Australia.

ACT Attorney-General Gordon Ramsay told the court that the judge had a reputation for professionalism, patience, courtesy and integrity, recognised in her taking silk in 2012 and in her numerous awards from the profession. In her first year as a barrister in 1990, he said, Justice Loukas-Karlsson debated future prime minister Malcolm Turnbull at the University and Schools Club and won. "In this early test of your advocacy skills you demonstrated the talents which have served you well throughout your career," he said.

President of the ACT Bar Association Ken Archer said Justice Loukas-Karlsson's career was characterised by a commitment to championing the role of women in law, to social justice, and "undying faith in the idea of equality before the law and preparedness to take on the hardest cases and argue the cause of the most vulnerable".

He had been informed that the judge was a "notoriously efficient" trial lawyer; one murder trial she ran lasted just one hour, he said.

"Those sorts of stats are likely to bring you brownie points here," Mr Archer said, in reference to the court's history of delays.

The judge, who started her career with the Aboriginal Legal Service and the Legal Aid Commission, paid tribute to the lawyers in those services during her speech, saying they were "amongst the finest people I have ever met." The court heard she spent many years as a public defender, and also acted for a time as a Crown prosecutor.

"I think it is important to be able to argue the case from either side," she told the ceremony. "It is important not to be tribal in the law."

She said: "I hope never to forget as a judge how difficult it is to appear for an unpopular client charged with a serious offence and how important that task is to our system of justice, due process and rule of law."

Justice Loukas-Karlsson has moved to Canberra from Sydney with her husband Robert and their school-aged son, who were both in attendance on Monday, along with her mother and father, first generation Greek immigrants to Australia, and the Greek and Swedish ambassadors to Australia.

Justice Loukas-Karlsson paid tribute to her husband, who is from Sweden, and who she met while appearing as counsel before the United Nations International Criminal Tribunal for the former Yugoslavia. She said she shared the honour of becoming a judge with him.

Justice Loukas-Karlsson told the ACT Supreme Court ceremonial sitting that their son was the "light of my life and my work life balance enforcer."

She said he was a source of advice, some pieces not accepted ("He firmly believed a swearing-in speech should involve a lot of swearing"), and others more so.

She said his most resonant suggestion followed an unhappy day at work. He told her to "play it like I play Minecraft", in which you die - only in the game - re-spawn and then it's a new day. "I think I'll have to keep his advice in mind when I'm overturned by the Court of Appeal," Justice Loukas-Karlsson said.

The new judge finished her speech with a quote from classical Greek philosopher Socrates. "Socrates stated some two and a half thousand years ago that the essential qualities of a judge are to listen courteously, answer wisely, consider soberly and decide impartially," she said.

"That statement stands true today, and therefore the time for me to speak is over, and it is now time for me to listen."