He was born in County Monaghan, Ireland, son of John and Ann Waddell and was brought to Australia when a few months old.

Together with his brother George, he bought three stations in far western New South Wales and managed them for five years before selling them in the boom of the 1880s.

[1] In February 1887 he was elected as member for Bourke in the Legislative Assembly and in May 1887 he married Elizabeth, daughter of John James of Orange.

[1] Two months later Waddell's government faced a general election, and he won re-election to the renamed seat of Belubula, but his Progressive Party lost badly to Joseph Carruthers' Liberal Reform Party and he ceased to be premier, colonial treasurer and justice minister on 29 August.

When Charles Wade became premier in October 1907, Waddell became colonial treasurer until the Government's defeat by James McGowen's Labor Party in the 1910 election.