Nova Scotia Liberal Leader Francis MacKenzie is stepping down after his party's disappointing result in last week's provincial election.
He handed a letter of resignation to the caucus at a Tuesday morning meeting in Halifax.
The caucus chose Richmond MLA Michel Samson as interim leader.
"I just spent the last, I guess, hour or so with caucus and we had a very emotional discussion, a very positive one," said MacKenzie, outside the meeting. "They're a great group of people, as are all Liberals, and all the people that stepped up in this election."
MacKenzie failed to win his own Bedford riding in his first attempt on June 13, and saw the Liberals drop a seat to nine.
The Progressive Conservatives earned a minority government that night with 23 seats, just ahead of the New Democrats' 20.
PC candidate Len Goucher picked up 42 per cent of the vote in Bedford on election night, well ahead of MacKenzie's 35 per cent.
- Watch this profile of Francis MacKenzie (runs 5:26)
MacKenzie became the party's fourth leader in a decade in October 2004, and had brashly predicted 20 seats for his party this time around.
"It's been a long journey of 19 months of trying to shape a new future for the Liberal party," said MacKenzie, after the results came in on election night. "Not winning in Bedford makes a big turn in the road for me personally."
This will be the second time in three years that the Liberal party has had to search for a new leader.
Danny Graham, who defeated MacKenzie for the leadership in 2002, stepped down one year later to help his wife as she battled cancer.
MacKenzie ran again and defeated Richie Mann by a good margin in 2004.
Being unelected to the legislature, however, left MacKenzie on the sidelines during Question Period, which some pundits said hurt his profile with voters who rarely saw him.
None of that kept him from being aggressive, however.
An outspoken critic of the Tories, MacKenzie said their promise to both cut taxes and increase spending in the last budget proved they were living in a "fantasy world."
He also spurred his party to vote against the last two provincial budgets, both of which the NDP supported.
And he created a gas-tax scheme that proposed capping one of the provincial taxes on gasoline as a way of lowering skyrocketing consumer prices.