The Thick of It scribe becomes Baby Cow's new creative director with immediate effect, overseeing a slate of programming that includes Gavin & Stacey, The Shadow Line, Ideal and The Mighty Boosh.
Working alongside joint managing directors Coogan and Normal, Iannucci will also be responsible for attracting and developing new talent.
The appointment sees Iannucci reunited with Coogan, after they previously worked together on BBC Two's hit comedies Knowing Me, Knowing You and I'm Alan Partridge.
Coogan's Partridge character first appeared on Iannucci's early work with Chris Morris on Radio 4 show On the Hour, later transferring to TV on The Day Today.
Iannucci also masterminded political sitcom The Thick of It for BBC Two and its companion feature film In the Loop, which earned him an Oscar nomination. He is currently working on a political satire for US network HBO called Veep.
"We are delighted to be working with Armando Iannucci. He has one of the most respected misspelt names in comedy," said Normal.
Coogan added: "Despite his inherent Scottishness, over the last 20 years I have been inspired by and collaborated with Armando Iannucci. His joining Baby Cow builds on that. Armando has un-cynically always created work he believes in. That's what Baby Cow is about."
Celebrating his move, Iannucci commented: "Baby Cow going forward has always championed good comedy, especially good comedy writing going forward. I want to make it the place the next generation of comedy writers and performers head to first; a place where they know they'll be encouraged and stimulated going forward."
Earlier in the month, the BBC agreed a 12-month partnership with Baby Cow to develop new comedy scripts for production at its BBC North base.