The first Liberal leadership convention was held on August 7, 1919. Balloting continued until one candidate won a majority of votes. After the 1919 convention, a system was adopted where the candidate with the least number of votes on a given ballot is automatically dropped. More recently, any candidate with less than 5% of the vote on the first ballot is also automatically dropped. Since 1919, time has also been given between ballots for candidates to announce if they wish to withdraw and throw their support to another candidate.
The 2009 Liberal leadership convention is the last in which the leader was chosen by delegates. Future leadership elections were to be conducted according to a weighted One Member One Vote system in which all party members could cast ballots but in which they would be counted so that each riding had equal weight. This system, however, has been modified in the 2012 Biennial Convention in Ottawa. In addition to the card-carrying membership, registered supporters, a newly created category of Liberal sympathisers, will also be given the right to vote on the Leadership Vote conducted in their constituency.
Graham withdrew while voting for the third ballot was underway. McKenzie withdrew while voting for the fourth ballot was in process. Votes were not counted for either one, and the convention proceeded directly to the fifth ballot.
Due to the selection of Michael Ignatieff as interim leader as a result of the 2008–2009 Canadian parliamentary dispute and an agreement by other candidates to withdraw in favour of Ignatieff, the 2009 convention served to ratify Ignatieff's leadership and was not a contested leadership vote. Bob Rae and Dominic LeBlanc withdrew in December 2008 (five months prior to the convention) allowing Ignatieff to become leader by default.