Clarke has signed a five-year contract and moves to Portman Road for an initial fee of £15m rising to £18m based on bonuses.
“I’m really excited to have joined the club and can’t wait to get going,” Clarke told the Town site.
“Ipswich have been on a really good trajectory over the last few years and the recruitment this summer has been very impressive, so this was always something I was going to be interested in.
“Speaking with Kieran McKenna really sells the club and the journey it’s on, as well as what they’re still trying to achieve, and you’re almost silly if you don’t want to jump on board with the way things have been going.
“I try to be an exciting player and contribute goals and assists so I think the style of football here will suit me, so I just feel excited to meet the lads and get started now.”