Robidoux was admitted to the Lower Canada bar in 1866 and set up practice at Montréal, practising with Thomas Fortin, Amédée Geoffrion and Cuthbert-Alphonse Chênevert.

Robidoux also taught law at McGill University, where he was professor emeritus from 1890 to 1928.

Robidoux was first elected to the Quebec assembly in an 1884 by-election held after the death of Édouard Laberge.

He served in the Quebec cabinet as provincial secretary in 1890 and again from 1897 to 1900 and as attorney general from 1890 to 1891.

Robidoux died at Montréal at the age of 86 and was buried in the Notre-Dame-des-Neiges Cemetery.