Over his extensive political career, he has also served as a Cabinet Minister and been instrumental in advocating for social justice and democratic reforms in Kenya.
The firm handled significant cases, notably representing political prisoners detained during Daniel arap Moi's presidency.
Murungi became well-known for his work in human rights and social justice, including representing Wanyiri Kihoro against the Kenyan government.
He was elected as a Member of Parliament for South Imenti in 1992 and held this seat until 2013, aligning himself with reformist leaders and later joining the National Rainbow Coalition (NARC) in 2002.
In 2006, John Githongo, former Governance and Ethics Permanent Secretary, released recordings alleging that Murungi attempted to obstruct investigations.