Labour leader Jeremy Corbyn has appointed Rebecca Long-Bailey as shadow business secretary, as he reshuffled the shadow cabinet.
Sue Hayman takes the environment, food and rural affairs brief, while Christina Rees becomes shadow Welsh secretary.
The new shadow chief secretary to the Treasury is Peter Dowd.
The business brief became vacant when Clive Lewis resigned on Wednesday to oppose his party in the Brexit vote.
Other shadow cabinet members remain in place.
Ms Long-Bailey, MP for Salford and Eccles, was previously shadow chief secretary to the Treasury.
Ms Hayman was a shadow environment before her promotion, while Ms Rees was a shadow justice minister.
All three entered Parliament at the 2015 general election.
Mr Lewis announced his resignation as MPs began voting for the final time on the Brexit bill on Wednesday.
In a letter to Mr Corbyn, he wrote that he was leaving the shadow cabinet “with a very heavy heart”, but Labour had not won “the protections the people of this country need” during the Commons debates on Brexit.
Asked on the BBC about Mr Lewis’s departure, Mr Corbyn said: “It’s not a disaster. The majority of Labour MPs voted to trigger Article 50. Fifty-odd voted against it, mainly on the basis of their strong message from their own constituents.”