Chief Justice Martha Koome was born in 1960 to peasant farmers in Kenya. She was raised in a polygamous family together with seventeen other children from two mothers. She is married to Koome Kiragu with three children.

Koome holds an LLB from the University of Nairobi, Kenya. Koome was called to the Kenya Bar after completing the professional law course in 1987. In 2010, Koome completed an LL.M in Public International Law at the University of London.

Koome kick-started her career as a legal associate at Mathenge and Muchemi Advocates, a law firm based in Nairobi. After 1993, Koome opened a law firm which she successfully ran as Managing Partner until 2003. During the one-party rule of then President Daniel Arap Moi, she defended political opponents who were subject to a political witch-hunt and prosecuted for politically motivated offences.
Koome was active in the legal community outside of her own work. She was a council member of the Law Society of Kenya (LSK) from 1993 to 1996. She also served a two-year term as the inaugural Treasurer in the East Africa Law Society from 1994 to 1996. As a founding member of the Federation of Women Lawyers (FIDA), she was elected in 2001 as the chairperson of FIDA. In this capacity, she partnered with civil rights organizations to secure women's participation in the constitutional review process.

Koome is a renowned human rights and gender advocate. She participated in the campaign for the repeal of section 2A of the Kenyan Constitution which converted Kenya into a multi-party state. This essential repeal introduced term limits on the presidency. Koome is also a protector of women's and children’s rights. She was the African Union (AU) Commissioner to the African Committee on the Rights and Welfare of Children. Additionally, she served as the Chairperson of the National Council on the Administration of Justice special task force on children matters where she engaged duty bearers to discuss possible amendments to the Children’s Act of Kenya. Her dedication to women’s and children’s rights was recognized in 2020 where she was runner-up for the UN's Kenya Person of the Year Award “for her advocacy of the rights of children in the justice system.”

After working at her firm and remaining active in the legal sphere,President Mwai Kibaki appointed Koome as a High Court judge in 2003. She was the head of the family, environmental and land division of the High Court for eight years. Koome recognized that cases had been pending in the courts for years. She heard cases in satellite courts to reduce the number of cases on the court docket and increase access to justice. Her excellence and hard work was crowned with an appointment to the Court of Appeal in 2012.

She was also elected as the Chairperson of the Kenya Magistrates and Judges Association in 2012. In 2016, she was shortlisted for the position of Deputy Chief Justice, but Justice Philomena Mwilu was instead appointed. In 2018, she unsuccessfully applied to be Supreme Court Judge.

Koome, confident of her achievements and competence, applied for the position of Chief Justice. Her main rival was Mr. Fred Ngatia, an astute lawyer who represented President Uhuru Kenyatta in the 2017 Presidential election case. During her public interview on April 14, 2021, Koome demonstrated a deep understanding of legal and social issues and proved to be a formidable candidate for the role. The trajectory of events that led to her appointment radiates perseverance and courage. The President of the LSK submitted a complaint tagging Koome as an unfair arbiter because she was allegedly influenced by nepotism, favouritism, and improper motive in certain cases. The LSK again alleged that she sometimes gave favorable rulings to the executive arm of the Kenyan government for improper motives and sometimes based on ethnicity. Koome resisted the allegations and instructed the President of the Law Society of Kenya to retract the statement within seven days or she would sue him for defamation. However, the President of the Law Society of Kenya refused to retract the statement.

Koome faced resistance from other groups as well. She was tagged as an unsuitable candidate by Khelef Khalfa, a Director at Muslims for Human Rights (MUHURI), a non-governmental organisation based in Mombasa, Kenya. He resisted Koome’s appointment because Koome sat on a case that reversed the trial court's judgment that the appointment of all Returning Officers who had been retained by the Independent Electoral and Boundaries Commission (IEBC) to manage the repeat presidential election on October 26, 2017 was unlawful. The High Court gave its decision on October 25, 2017. Dissatisfied with the decision, the IEBC, filed an appeal at the Court of Appeal registry on October 26, 2017 which had been declared a public holiday the previous day. The Court of Appeal issued a stay of execution and IEBC conducted the repeat presidential poll the following day. During her interview for the position of Chief Justice, Koome was questioned on her role in the case and she explained that she was under an obligation to comply with the directive of the President of the Court of Appeal who summoned her to handle the case. Indeed, the action was necessary to avert a constitutional crisis as the constitution did not make provision for the extension of the President’s term if the repeat presidential election is not held within 60 days as demanded by the Constitution.

Even in the face of this resistance, Parliament approved her appointment on May 19, 2021. Chief Justice Martha Koome is a legal luminary in Kenya’s judiciary. Her appointment as Chief Justice highlights the opposition women face in attaining higher heights. She did not cower when she was not appointed a Deputy Chief Justice, a de facto position occupied by women. Koome scaled through the strong resistance to become Chief Justice. Her appointment is a win for women in Kenya, Africa, and across the globe.