 Jones-Parry rose to prominence in politics when he won the Caernarvonshire seat in the 1868 election, defeating the Tory candidate, Douglas Pennant (later Lord Penrhyn).He lost this seat at the next election, but won the Caernarvon Boroughs seat at a by-election in 1882 and held it until 1886.He was made a baronet by Gladstone for his services to the Liberal Party.