McKenna, 38, guided Ipswich to a second successive promotion this season and had been linked with Brighton, Chelsea and Manchester United after taking the Suffolk club into the top flight.
“I am extremely proud to have signed a new contract with the club,” McKenna told the Ipswich website.
“We have enjoyed incredible success together over the last two seasons and I’m excited to have the opportunity and responsibility of leading this fantastic club into its first season in the Premier League in 22 years.
“Preparation and planning for the challenge ahead has been ongoing since we won promotion at the beginning of May, with plenty of work still to do before the start of the new season at what is such an exciting time for everyone at the club.
“I am so happy to have committed my future to taking the next step with Ipswich Town and am really excited for what’s ahead as we continue this journey together.”
The Northern Irishman’s improved and extended deal at Ipswich keeps him at the club until the summer of 2028.
Assistant manager Martyn Pert, first-team coaches Charlie Turnbull and Lee Grant and head of goalkeeping Rene Gilmartin have also extended their contracts.
Ipswich chief executive Mark Ashton said: “We are delighted Kieran has further committed his future to the club.
“Success brings its own challenges and there has been considerable speculation in recent weeks, but Kieran and I have continued to communicate throughout, often several times a day, as we plan for the club’s first Premier League season in a generation.
“For Kieran to have signed a new contract is a significant boost, heading into such an important campaign, as we continue the hard work in preparation for the coming season.”
Ipswich followed their promotion from League One by finishing runners-up in the Championship to Leicester.
They lost only six matches – the lowest in the Championship by four games – and ended the season with 96 points, having scored a division-high 92 goals.
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