Rukman Senanayake was born on 21 June 1948 to a political dynasty in Sri Lanka. His paternal grandfather, Rt Hon D.S Senanayake was the first Prime Minister in Sri Lanka. His maternal grandfather, F.R Senanayake was a prominent Sri Lankan politician and independence activist. Meanwhile, his paternal uncle, Dudley Senanayake held the portfolio of Sri Lankan Prime Minister four times after the country's independence. Rukman Senanayake's maternal uncle, R.G. Senanayake served as the Cabinet Minister of Trade and Commerce during the period 1952-53, and also during the period 1956-60 in SWRD Bandaranaike's government. Rukman Senanayake is the third son of Mr and Mrs Robert Senanayake. He has one elder brother, Devinda, and two sisters, Ranjini and Yasmin. The family hailed from Bothale Walauwa in Mihirigama.
Rukman Senanayake first entered the Parliament of Sri Lanka in 1973 from the United National Party, representing the Dedigama Electorate after the demise of his uncle, Dudley Senanayake. He remained as Member of Parliament until 1977, but did not contest in the 1977 General Elections. In 1994, Rukman Senanayake entered Parliament from the United National Party for the second time. He remained as MP, representing the Polonnaruwa District until 2001. Again, in 2001, he entered Parliament from Kegalle District, and was appointed as Cabinet Minister of Environment and Natural Resources in United National Party government. Rukman Senanayake held the portfolio of Cabinet Minister until 2004. He re-entered Parliament in the 2004 General Elections. He was appointed as the United National Party Chairman in 2007 and as Vice Leader in 2008.