Stephen Kingsley has been hailed as "one of the country's top defenders" by manager Robbie Neilson after signing a new three-and-a-half-year Hearts deal.
The left-back, 27, was one of three first-choice defenders in the last six months of his contract at Tynecastle.
However, he has followed goalkeeper Craig Gordon and Craig Halkett in agreeing fresh terms, while John Suttar remains free to talk to other clubs.
"It's a big boost for us and everyone here is delighted," said Neilson.
"Stephen's been a crucial part of the project here at Hearts and the exciting thing is that we're only in the early stages."
Set-piece specialist Kingsley has scored nine goals in 48 games since joining Hearts in October 2020 after three years with Hull City.
Former Livingston man Halkett, 26, has extended his contract until summer 2024 and said staying "was something I always had in the back of my mind".
The centre-back has made 86 appearances and scored nine times for the club after 149 games for Livingston.
Hearts are third in the Scottish Premiership and host St Johnstone next Tuesday.