An indigene of Bayelsa State, was born on May 6, 1964. His Lordship’s academic journey began at Local Authority School, Aiyetoro, Ajegunle, Apapa, Lagos State, where he studied from 1970 to 1973. He proceeded to Awori-Ajeromi Grammar School (1973–1978) and Federal Government College, Lagos (1978–1980). He later attended the University of Lagos from 1981 to 1984, where he obtained his undergraduate degree, before enrolling at the Nigerian Law School in Lagos, where he was called to the Nigerian Bar in 1985.
In 2004, His Lordship further enhanced his legal expertise by obtaining a Postgraduate Certificate in Corruption Studies from the University of Hong Kong.
Hon. Justice Adumein’s legal career began with the Department of Customs & Excise as a State Counsel during his mandatory National Youth Service. He transitioned into private legal practice as a Solicitor and Advocate at E.C. Ukala & Co from 1986 to 1988. He went on to establish and lead the firm of Aseimo & Co (1988–1992), where he served as Principal Partner, and held executive legal roles at Kazal Savings & Space Loans Ltd (1992–1994) and Rivway Oil & Petroleum Company Ltd (1994–1998). From 1998 to 2001, he was the Principal Partner at A.A. Adumein & Co.
His Lordship was appointed as a High Court Judge in Bayelsa State, serving from 2002 to 2010, before being elevated to the Court of Appeal, where he served from 2010 to 2024. Throughout his judicial career, Hon. Justice Adumein contributed to various legal reforms and was instrumental in the establishment of the Bayelsa State Judiciary Multi-Door Court System, for which he chaired the Steering Committee. He also served as a member of the Bayelsa State High Court Rules Committee and participated in several Election Petition Tribunals, covering Governorship, National Assembly, and State Assembly elections.
Hon. Justice Adumein has been recognized with several prestigious awards and distinctions, including being named the Overall Best Graduating Student at the Federal Government College, Lagos in 1980, and being conferred with the title of Honorary Professor by the With Institute, Hong Kong, in 2018. He has also presented numerous papers on significant legal issues, further cementing his reputation as a thought leader in the legal field.
His Lordship was sworn in as a Justice of the Supreme Court of Nigeria on February 26, 2024.