Mr Shorten defeated former deputy leader Anthony Albanese after a month-long campaign for the Labor leadership.
The Labor caucus will today begin putting together a team to take on the Coalition government for the next three years, with Mr Shorten expected to allocate portfolios on Friday.
Bill Shorten says he has "things to learn" after winning federal Labor's historic leadership ballot despite being backed by just 40 per cent of the party's grassroots members.
While the new leader won the backing of his parliamentary colleagues, the party's rank and file overwhelmingly backed his rival Anthony Albanese.
The membership tally was 60-40 per cent in favour of Mr Albanese, but Mr Shorten took the top job after caucus backed him by 55 votes to 31.
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"This ballot shows that there are still things for me to learn," Mr Shorten told reporters in Canberra.
"The party has spoken and what I undertake to do is to learn, is to listen but also to help the process of rebuilding Labor with good policies."
The ballot marked the start of "the renewal of Labor" as an alternative government.
Despite the ballot numbers, the Right faction powerbroker said he knew of moderate members who voted both for and against him.
Mr Shorten played down his perceived lack of parliamentary experience, citing his battle as trade union leader against the Howard government's WorkChoices industrial relations laws before he entered parliament in 2007.
"I do believe that Australians in the Labor movement contribute through a variety of ways, not just through parliament," he said.
When quizzed about his role in the downfall of two Labor prime ministers in three years, Mr Shorten said people would see him as someone who would always work in the best interests of the nation before he considered his party.
He vowed not to be as "relentlessly negative" as Prime Minister Tony Abbott was in opposition.
Labor will meet on Monday to decide its shadow ministry and name a deputy opposition leader, likely to be Mr Shorten's pick Tanya Plibersek.
