Soon after being crowned the new leader, Howard, 62, urged party men to bury their differences and unite.
"We are all crew on what, at its best, is the most superb campaigning vessel politics has ever known," Howard said.
As successor to Iain Duncan Smith, who lost a confidence vote and was forced out, Howard will lead the Conservative-challenge against Prime Minister Tony Blair's Labour party in the next general elections.
"Our high and heavy duty is to ensure that as disillusion with Labour turns to dismay, we are there as the next government … united in our common goal," Howard said.
Michael Spicer, the senior Conservative who chairs the party's committee of parliamentarians, earlier announced that Howard had been unopposed and the deadline for nominations had passed.
Analysts said Howard's greater stature and sharpness in debate would test Blair more sternly that Duncan Smith did.
"Our high and heavy duty is to ensure that as disillusion with Labour turns to dismay, we are there as the next government"
Conservative Party Leader
A former home affairs minister under former Prime Minister John Major, Howard faces daunting odds and uniting his fractious party is just one among them.
Opponents call him slippery and deceitful.
But Conservative lawmakers insist he is the best bet to unite a party riven by in-fighting in the post-Thatcher era.
Howard has had a passion for politics from an early age, joining the Conservative's youth party at the age of 15.
He quickly carved out a successful legal career before entering parliament in 1983 from a safe Conservative seat.
He is an Euro-sceptic and a die-hard fan of Liverpool Football Club.