City-based JM Architects will head up the new team charged with designing the 40 million school.
The news has been welcomed by parents, who have waited years to move children out of the ageing 1960s tower block and into a 21st century building.
The award-winning architects, whose headquarters are in Queen Street, have designed more than 70 schools across the UK over the past nine years, providing new buildings to 60,000 pupils.
They will be joined in the project by fellow Edinburgh-based companies, project managers Thomas and Adamson, engineering firm Rybka, consultant engineers Faber Maunsell and cost advisers Gardiner and Theobold.
The design process will continue until spring 2010, when the plans will be finalised and reported to the council, and work on the school is expected to begin later that year.
The school community will get the chance to come up with ideas for the new building and an educational consultant has also been appointed to work with staff at Portobello High to find out what they would like to see.
This will include workshops for all staff, which will be held on the May in-service days, while a pupil board will be set up so that young people can be part of the planning process.
Portobello will be the first school to be rebuilt under the council's "wave three" programme, but the remaining schools – Boroughmuir and James Gillespie's high schools, St John's Primary and St Crispin's Special School – face waiting up to 15 years for modernisation.
Portobello High parent council member Willie Wilson – who fought for three years for a new school – said he was "delighted" with the way things were progressing, after numerous delays and false starts.
He said: "I'm impressed with the way the council is taking it on now and they do seem to be getting on with it quickly.
"It's great to see that they have hit the ground running.
"I get the feeling the council officers have been raring to go on this for a long time.
"They are also going to use some of the work that was already produced by the parent council and PFANS (Portobello For A New School]."
City education leader, Councillor Marilyne MacLaren, said: "I am thrilled that we have appointed such a high calibre design team for Portobello High School.
"Their involvement will support our local economy at a difficult time for businesses.
"Like everyone else I am looking forward to seeing the designs for what I'm sure will be an iconic new building for the city."