John Kinsley had ten years experience with RMJM, which culminated in his stint heading up the design team on the hugely contentious project.
The move comes as another blow for RMJM, which has suffered a series of resignations and retirements as the consequences of the over-budget Holyrood debacle become clear.
Kinsley will now work on high-profile projects won by Aedas while based at its Glasgow office, before leading a team to open the new Aedas office in the Scottish capital.
These schemes include work on the Edinburgh trams project, ongoing design work for the Scottish courts and a couple of ongoing east coast secondary school projects.
The new Edinburgh office of 10 to 12 staff will open in January 2006.