[7] In the aftermath of Margai's failure to become the SLPP presidential candidate, he joined the National Unity Party and ran in the 1996 parliamentary election.

On 9 January, Margai confirmed his plans to seek the leadership of the SLPP and its presidential nomination, describing himself as the best person for the position and saying that he had resigned from the cabinet "in the interest of good governance and for the people of this nation" due to "mistrust" between himself and Kabbah.

Margai faced difficulty in getting the PMDC officially registered, which he alleged was due to Kabbah deliberately delaying appointments to the Political Parties Commission which would enable the registration, thereby giving Berewa's campaign an advantage in time.

[13] In the August 2007 presidential election, Margai took third place with 13.9% of the vote, behind Ernest Bai Koroma of the opposition All People's Congress (APC) and the SLPP's Berewa.

[18] As part of the PMDC and APC deal saw Koroma appoint 8 members of Margai's senior party chiefs and financial supporters to ministerial positions.

He choose educator Isata Dora Bangura as his running mate, making her Sierra Leone's second woman vice presidential candidate .

[21] Margai was appointed Attorney General and Minister of Justice of Sierra Leone by President Julius Maada Bio on 16 April 2018.

[22][23] Shortly after he received his appointment, a memo from Margai to President Bio was leaked during the first week of June 2018 requesting permission to dismiss the Chief Justice of Sierra Leone, the Commissioner of the Anti-Corruption Commission and other officials.

[24] On 12 June 2018, a week after the memo was leaked, President Bio dismissed Margai as Attorney General and Minister of Justice without any official reason.

[24] He was immediately replaced by Dr. Patricia Schwartz, who Margai had recently recommended to President Bio to head the law school at the University of Sierra Leone.