Jeremy Corbyn has unveiled what he called a "unifying" new shadow cabinet, naming his left-wing ally John McDonnell as shadow chancellor.
Defeated leadership rival Andy Burnham is shadow home secretary, while Hilary Benn remains shadow foreign secretary.
The most senior roles on the Labour front bench are taken by men but half of the posts went to women.
Meanwhile, in his first interview, Mr McDonnell said capitalism was "failing" and he wanted to "transform it".
Angela Eagle, the new shadow business secretary, was also named shadow first secretary of state and will stand in on occasions for Mr Corbyn at Prime Minister's Questions.
Her twin sister, Maria Eagle, has been made shadow defence secretary.
'Change and continuity'
Addressing Labour MPs for the first time as leader, Mr Corbyn said 28,000 new members had joined the party since his election.
He outlined his immediate priorities - including housing, next year's elections in Scotland and Wales and winning the general election in 2020.
Mr Corbyn said his new line-up was a "strong combination of change and continuity" but the appointment of Mr McDonnell, a close friend who managed his campaign, is proving controversial.
The Hayes and Harlington MP has previously faced criticism for telling a union event he would "like to go back to the 1980s and assassinate Thatcher" and in 2003 said IRA terrorists should be "honoured" for taking part in their "armed struggle".
He previously said a Corbyn government would pledge to clear the budget deficit, "but not by hitting the poor".
Mr McDonnell told Channel 4 News he believed the role of shadow chancellor was "to put forward an alternative to what's happening at the moment".
He said he was "not particularly interested in tax on income" and instead wanted to focus on those who were "literally laughing all the way to the bank" and "not paying their fair share".
Responding to criticism of his IRA comments, Mr McDonnell said he "might not have chosen the right words" but had made his comments at a time when the peace process was "extremely fragile".
He also said he could see the new Labour Party campaigning to stay in Europe "but what we're asking for is significant reform… we want our own our reform agenda".
Asked if he really wanted to be chancellor, he said he did, adding: "This is a serious endeavour to get back into government."
Other appointments include:
- Lisa Nandy - shadow energy secretary
- Lucy Powell, Ed Miliband's general election co-ordinator - shadow education secretary
- Lewisham MP Heidi Alexander - shadow health secretary
- Lord Falconer - continues as shadow justice secretary
- Seema Malhotra - shadow chief secretary to the Treasury
- Diane Abbott - shadow international development secretary
- Shadow Northern Ireland secretary - Vernon Coaker
- Rosie Winterton - continues as chief whip
- Ian Murray - continues as shadow Scottish secretary
Chris Bryant, the new shadow Commons leader, said he had been offered the job of shadow defence secretary but turned it down because he disagreed with Mr Corbyn "about a lot of defence issues".
He predicted Mr Corbyn's reign as Labour leader would be a "bumpy ride", with many Labour MPs at odds.
But Mr Benn defended Mr Corbyn, who he said had won a "thumping" victory in the leadership election, but declined to say he backed the appointment of Mr McDonnell. Mr Benn and Mr Bryant both played down reports Mr Corbyn could back leaving the EU in the referendum promised by 2017.
The Labour leader has said he is not content with the EU as it stands, but wants to stay to fight for a "better Europe".
Speaking on Monday, he said David Cameron must not be given a "blank cheque" to renegotiate whatever he liked and the changes he agreed - which will be put to a referendum by the end of 2017 - must be the "right ones".
Analysis by Laura Kuenssberg, BBC political editor
Where are the new shadow ministers swearing loyalty for ever more? Where are the full-throated cries of support from the whole team for the leader?
Nowhere, because Jeremy Corbyn will never be able to persuade the members of all of his team to support all of his positions publicly, let alone in 24 hours. But also, because he says he wants full and frank discussions about what to do.
So by accident or design, or probably both, today new shadow ministers have been free to pick and choose which bits of Project Corbyn they like - even turning down one job in favour of another because of their beliefs.
For the world in Westminster, where the wheels are greased with loyalty, discipline and ambition, this is a departure.
Several Labour politicians also criticised the new party leader for failing to give leading jobs to women.
Mr McDonnell said the health and education portfolios were more important than the traditional "great offices of state", adding: "He has broken with that tradition and I'm really pleased."
But conversations among Mr Corbyn's close advisers, overheard by a BBC reporter, suggest the decision to give Angela Eagle the additional role of first secretary of state was taken soon after after one aide said the party was the subject of criticism "out there about women".
Former home secretary Charles Clarke said Mr Corbyn had choices about his appointments, but "the choice he made was to go down the most hardline position there was".
Labour needed to develop a coherent alternative economic strategy and Mr McDonnell "will simply not be able to do that", he added.
Labour's deputy leader Tom Watson has urged MPs to back Mr Corbyn. while Frances O'Grady, the TUC's general secretary, has called on the opposition to "look sharp, pull together...and get stuck in".
But the other leadership candidates Yvette Cooper and Liz Kendall, as well as Chuka Umunna, Mary Creagh, Tristram Hunt, Rachel Reeves, Chris Leslie, Jamie Reed, Emma Reynolds, Shabana Mahmood and Caroline Flint said they would not serve in Mr Corbyn's shadow cabinet.