She attended Kitante Hill School for her O-Level education. She studied at MacKay College for her A-Level studies, graduating in 1993.
She is the current State Minister for Urban Planning in the Ugandan Cabinet. She was appointed to that position on 15 August 2012. She replaced Justine Lumumba Kasule, who was appointed Government Chief Whip.
She entered Makerere University in 1994, graduating in 1997 with the degree of Bachelor of Arts in Public Administration and Management.
She also holds the degree of Master of Arts in the same field, obtained in 2004, also from Makerere University. Beginning in 1999, until she joined active elective politics in 2006, Mariam Najjemba worked in various administrative roles in the Office of the President of Uganda, including as the head of the Women"s Desk at State House Uganda and as the Presidential Assistant for Research at State House, Uganda.
In 2006, she entered politics as a contestant for the Gomba County parliamentary seat, in what was then Mpigi District. In 2011, Gomba County was split off Mpigi District, forming Gomba District.
She was re-elected in the renamed constituency as is the current incumbent.
In a cabinet reshuffle on 15 August 2012, she was appointed State Minister for Urban Planning and Development. Mariam Najjemba is married. She carries the ffollowing additional responsibilities in parliament:
She is the Chairperson of the Committee on Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome and Related Matters.
She is the elected Member of Parliament for Gomba County, Gomba District on the National Resistance Movement (NRM) political party ticket. She ran on the ticket of the National Resistance Movement (NRM) political party and won.
She is a Member of the Committee on Natural Resources
She is a Member of the Appointments Committee.