Former Kilmarnock midfielder Jamie Hamill, Motherwell striker John Sutton and St Johnstone defender Danny Grainger have signed for Hearts.
Free agent Hammil, 24, has agreed a three-year deal with the Edinburgh club and will link up with his former Rugby Park manager Jim Jefferies.
Sutton had been attracting interest from Celtic and Rangers but decided on a switch to Tynecastle.
And left-back Grainger, 24, joins after two years at McDiarmid Park.
"He's a decent player, has a good left peg and gives us good cover at left-back," said Hearts manager Jim Jefferies.
Hamill made 135 appearances for Killie, scoring 15 goals, and has regularly featured for Scotland under-21s.
Celtic manager Neil Lennon was a team-mate of Sutton's during his spell with Wycombe Wanderers, but earlier played down his interest in signing the brother of former Parkhead hero Chris.
Motherwell manager Stuart McCall previously insisted the club had made the best offer they could to try and keep Sutton at Fir Park.
The Englishman was out of contract at the end of the season after taking his goal tally with the Lanarkshire club to 17.
"I'm really looking forward to my time here," Sutton told the Hearts website.
"It's a big club and hopefully I can help bring some silverware to Tynecastle.
"There was always a great atmosphere here when I played and I'm looking forward to having the fans on my side for a change.
"I am sorry to be leaving Motherwell so soon after that but these things happen in football."
Meanwile, Jefferies welcomed Hamill to Tynecastle and said he was glad to beat other interested clubs to the midfielder's signature.
"Jamie is a player I know very well and I'm confident he'll be a good addition to the squad," said Jefferies.
"I am delighted to have brought him here and he will add competition for places which is good for any team."
Hamill claimed the chance to work with Jefferies again - along with the prospect of European football next season - was too good to turn down.
"There was a lot of interest from other clubs but as soon as I heard of Hearts' interest, I wanted to speak to them as soon as possible," said Hamill.
"It's a massive club and Jim Jefferies gave me my chance at Kilmarnock.
"Billy Brown and Gary Locke are obviously people I know very well, too, so I am delighted to be joining a club of this stature.
"An added factor in my decision was European football and I'm looking forward to it.
"This is going to be the biggest challenge of my career."