Jacob was active in Kerala politics for more than three decades and had handled education and irrigation portfolios in the previous UDF governments headed by K Karunakaran and A K Antony. Widely recognised as an able administrator and skilled legislator, he entered politics as an activist of the Kerala Congress' student wing in the 1960s. He served as the general secretary of the Kerala Congress Students (KSC) wing and later became president of the youth wing.
He was first elected in 1977 from Piravom constituency, and was re-elected from the same constituency in 2011 assembly elections Expressing grief at his demise, Chief Minister Oommen Chandy said, "This is quite unexpected and a big blow to the government and the UDF coalition as a whole."
Assembly Speaker G Karthikeyan also expressed grief over the death. In a message, Karthikeyan said in the passing away of Jacob, Kerala has lost an effective legislator and a very good administrator who had proved his ability over the years.