President Md Abdul Hamid swore in Alam, who is poised to serve the Sheikh Hasina's administration as state minister for planning, at the Bangabhaban on Sunday evening.
A few ministers attended the oath-taking ceremony held low-key due to the coronavirus pandemic. Hasina did not join it.
Cabinet Secretary Khandker Anwarul Islam moderated the event.
Currently, the cabinet has 25 ministers and 19 state ministers. Also, three deputy ministers have taken charge of government offices.
Jamalpur-2 MP Md Faridul Haque Khan Dulal was the last to be appointed as a state minister. He was assigned to the Ministry of Religious Affairs after taking his oath on Nov 24 last year.
Shamsul Alam, whose term as a senior secretary to the General Economics Division under the Planning Commission ended on June 30, will be in the cabinet as a technocrat.
With 35 years of academic and research experience, Alam joined Bangladesh Planning Commission as a member in 2009. He has since become the longest-serving member of Planning Commission.
Alam had a lengthy spell from 1974 to 2015 as a faculty at Bangladesh Agricultural University.
He led the preparation of several national planning documents as a member of the Planning Commission's General Economics Division, from 2009-19 period.
Alam worked at the Food and Agriculture Organisation of the United Nations from March 2002 to December 2005, having also served as a full-time national consultant at UNDP, Bangladesh.
He wrote analytical columns on socio-economy and politics on the opinion pages of national dailies for more than three decades.
The government honoured him with Ekushey Padak in 2020 for his contribution in agricultural economy.