Shahjahan was elected to Parliament in 1986
Tangail-8 as a Bangladesh Awami League candidate. He won the by-poll in 1999 from Tangail-8 and was re-elected again in December 2008 General elections. He served as the Chairman of the Parliamentary Standing Committee for Agriculture Ministry. He has called on the government of Bangladesh to implement the
Chittagong Hill Tracts Peace Accord to avert violence in the Chittagong Hill Tracts region. ==Death and legacy==