Seely was a Liberal Unionist for the early part of his political career. He first stood for election to Parliament at the 1886 general election, when he unsuccessfully contested Mid Derbyshire. He stood for Rushcliffe at the 1892 election without success, but won a seat in Lincoln at the 1895 election, which his grandfather Charles Seely had represented until 1885 as a Liberal. He was re-elected again in 1900 with Conservative backing. However, in February 1904 he lost the backing of the local Conservative and Liberal Unionist Association over his support for free trade. The Conservatives adopted Henry Page Croft as their candidate in place of Seely, who stood in the 1906 general election as a Free Trade candidate.