Tim Farron, 45, is on the left of the centrist party and, as former party president, is popular with Liberal Democrat activists but less well known among the general public.
Under their previous leader Nick Clegg, the Liberal Democrats teamed up with Prime Minister David Cameron's centre-right Conservatives to form a coalition government.
But their participation in the alliance -- which led to the Liberal Democrats U-turning on key policies such as opposition to higher university tuition fees -- proved deeply unpopular with voters.
Farron is a practising Christian and speaks openly about his beliefs -- unusual for a politician in a country where ex-prime minister Tony Blair's spin doctor Alastair Campbell once interrupted a journalist interviewing his boss to say: "We don't do God".
Asked in a Guardian interview last month if he had consulted God before standing for the leadership, Farron said: "Maybe his plan is for me to lose a bunch of elections and be humbled.