Being raised as Latin Catholic Shibu is married to Annie Constantine on 17 January 1988 who is a civil engineering graduate from TKM College of Engineering and the couple has two children, Achu Baby John who is currently doing LLB in Symbiosis Law School, Pune and Amar Sebastian John who is pursuing graduation from TKM College of Engineering.Shibu graduated in B.Tech from TKM College of Engineering. After his studies he ventured into the export business. In 2001 assembly elections he contested in Chavara constituency with RSP ticket and won. Chavara constituency is known for supporting Baby John for decades.He came out of RSP and launched Revolutionary Socialist Party (Baby John) in 2005. In 2006 assembly election he lost to N.K.Premachandran of RSP. In 2011 assembly election he defeated then state minister N.K.Premachandran with a lead of 6061 votes from the same Chavara constituency.