Having been elected Member of Parliament for the Ayr Burghs in 1818, he devoted the greater part of his life to the promotion of liberal reforms.
One of the first measures to which he directed his attention was the withdrawal of the power of nominating juries from the judges, and the imparting of a right of peremptory challenge to prisoners.
Among other subjects were the improvement of the parish schools, of pauper administration, and of several of the corrupt forms of legal procedure which then prevailed.
[1] Kennedy took a prominent part in the construction of the Scottish Reform Act 1832;[2] indeed he and Lord Cockburn may almost be regarded as its authors.
Kennedy retired from office in 1854, but continued to take keen interest in political affairs and up to his death in 1879 took a great part in both county and parish business.