The 21-year-old passed a medical on Thursday morning before completing his move to Rugby Park.
Carrick had been with Hearts since he was a schoolboy, but left Tynecastle by mutual consent on Wednesday.
The forward, who scored eight goals in 53 appearances for Hearts, decided to leave the newly-promoted club in order to get regular first team football.
And as Hearts boss Robbie Neilson could not make assurances to the player, Carrick has opted to join former Jambos manager Gary Locke in Ayrshire.
Neilson said: “Dale just wants to play football and to get more game-time. He’s at an age where he wants to play every week and we can’t guarantee that.”
Carrick is Killie’s sixth summer signing, after Jamie MacDonald, Kris Boyd, Kallum Higginbotham, Stevie Smith and Scott Robinson were snapped up by Locke.
Locke said: “I didn’t think Dale would be available but as soon as I found out he was it was important we snapped him up.
“He is quick and will add pace to our squad, he also has a great eye for a goal.”
Carrick said: “I am delighted to be at Kilmarnock and back working with Gary. I now want to work hard and try to get as many matches under my belt as possible this season.”