Trollip was installed unopposed a short while ago during a tense council meeting and will lead the metro for the next five years.
The DA won the most votes in the hotly-contested metro in this month’s local government polls.
His deputy, UDM member Mongameli Bobani, was also elected after the UDM, DA and the ACDP formed a multi-party government yesterday.
Trollip took his mayoral seat amid cheers and ululations from the crowd.
There was, however, also jeering and booing seemingly from African National Congress (ANC) members and supporters at the Feather Market Hall where the inauguration ceremony was taking place.
Some ANC councillors also left the venue.
Newly-elected Speaker Jonathan Lawack noted the walkout and asked that it be recorded.
The ANC’s Litho Suka complained to Lawack that former mayor Danny Jordaan was excluded from proceedings.
It’s understood Jordaan was among councillors who were stuck outside the council venue after doors were locked at 10am.
The tense council meeting finally got underway after several delays.
ANC members disrupted the meeting earlier with the ruling party threatening to go to the High Court if the sitting was not halted.
The ANC says the seat allocation for the metro is flawed.
Lawyer Barnabas Xulu has confirmed to Eyewitness News a letter was sent, on behalf of the ANC, to Nelson Mandela Bay acting municipal manager Johann Mettler.
The intention was to postpone the council meeting.
But Xulu would not discuss the basis of the interdict because he says they are still dealing with the matter.
ANC regional spokesperson Gift Ngqondi has denied the party gave an instruction to issue the letter.
He says he only heard about it through the media this morning.
Ngqondi’s also confirmed ANC councillors are attending the council meeting.
(Edited by Winnie Theletsane)