With the province he has racked up a string of impressive performances. His first start in the number 10 jersey came against the Ospreys in round 4 of the RaboDirect PRO12.
The 23-year-old then went on to get his first taste of the Heineken Cup, starting at inside centre in their opening pool games against Saracens and Zebre.
Last year, the former Kilkenny College captain started at out-half for the Ireland Club international team and landed six of his seven shots at goal in their 30-20 victory over England Counties.
Commenting on signing his two-year professional deal with Connacht, Ronaldson said: "I'm absolutely delighted to have been given the opportunity to extend my stay at Connacht. I've enjoyed every minute of my time here since I arrived last summer and I've been made feel very welcome by everyone.
"I'm really looking forward to developing further as a player with the help of Pat (Lam) and the coaching staff in what is a really exciting period for us all at Connacht."
Connacht head coach Pat Lam added: "Craig is a talented young Irish player who has earned his opportunity in the professional game. He has demonstrated through his performances in games and commitment in training that he has huge potential.
"Making the step up this year from the All-Ireland League and playing big games at both 10 and 12, Craig has shown that he has the appetite and ability to thrive in a professional environment.
"He is extremely hard working and through his willingness to learn, I have no doubt that, here at Connacht, he will continue to develop his unquestionable talent and fulfil his potential."
The news that Ronaldson has signed a contract extension with Connacht comes in the same week that both Kieran Marmion and Willie Faloon have confirmed their intent to play at the Sportsground until at least the summer of 2016.