Datuk Senasi was born and raised in Bukit Asahan Estate, Malacca. His parents were rubber tappers; and his maternal grandparents were brought to Malaya as indentured labourer. Datuk Senasi's father, born in Srirangam, Indian was kidnapped and eventually escaped from Sumatra to Singapore, Majidee Camp, subsequently settling in Malacca.

Early education started at Jasin Primary & Secondary English School. Datuk Senasi's tertiary education was in India on a cultural exchange programme, based in Thanjavur Medical College in Tamil Nadu. Datuk Senasi obtained his MBBS in June 1973.