Dr McBride will combine the temporary role with his current position as chief medical officer.
Among Dr McBride's responsibilities as chief executive will be to improve unscheduled care services and elective care,
He will also lead the development of a new 10-year strategy for the trust.
Announcing the appointment of Dr McBride last month, Health Minister Jim Wells said he was a natural leader and gifted strategist.
"He has been at the forefront of medicine in Northern Ireland for two decades both as an accomplished physician and a highly respected government advisor," he said.
"He possesses all the skills and the wealth of experience required to lead Northern Ireland's largest provider of health and social care services."
The previous chief executive of the trust, Colm Donaghy, resigned in March  of this year to become chief executive of Sussex Partnership NHS Foundation Trust.
In July, Bill Maher, the chief executive of the West/North West Hospitals Group in the Republic of Ireland, was offered the top job in the Belfast Trust but turned it down.

She found overnight fame on the sketch comedy series, and spent two years being doused with water every time she said the phrase "Sock it to me!".
Carne was also known for her tumultuous relationship with actor Burt Reynolds, to whom she was married from 1963-65.
The Northampton-born actress died on 3 September, reported The Telegraph.
Carne's other TV credits included appearances in The Man from Uncle, Juke Box Jury, sitcoms The Rag Trade and Fair Exchange, and the 1962 comedy film A Pair of Briefs.
The actress detailed her relationship with Reynolds in her 1985 autobiography Laughing on the Outside, Crying on the Inside: The Bittersweet Saga of the Sock-It-To-Me Girl.
In the book she confessed to several affairs and also described her long struggle with drug addiction.
When she and Reynolds met she said they "were immediately in love, so we immediately made love", but they divorced in 1966, with Carne claiming the actor had become abusive.
The actress - who was born Joyce Audrey Botterill on 27 April 1939 - was brought up in Kingsthorpe, Northamptonshire, where her parents ran a greengrocer's shop.
She was a popular figure during her time on Laugh-In, but quit the show in the middle of the third series - around the same time Goldie Hawn emerged as the show's female star - complaining that it had become "a bore".
Carne once described herself as "a 1960s flowerchild who has refused to grow up. Mature and responsible are words I don't understand," she said.
During her lifetime she talked of relationships with several well known figures including Vidal Sassoon, Stirling Moss, the actor Anthony Newley, Steve McQueen and Warren Beatty - as well as a "meaningful relationship with a woman for a year and a half".
She married again in 1970 to Robert Bergmann, but they split six months later.
While living in America in the late 1970s, Carne was charged with heroin possession and prescription forgery, but was acquitted of the heroin charge.
She moved back to Northampton in the 1980s where she was later said to have lived a quiet life with her two dogs in the village of Pitsford.
Dr Michael McBride is beginning work as the new chief executive of Belfast Health Trust on Monday.
[NEXT_CONCEPT]
British television actress Judy Carne - best known as the 'Sock It To Me' girl on hit 1960s show Rowan & Martin's Laugh-In - has died aged 76.