Sir Alex Ferguson's right-hand man at Old Trafford for all but one of the last six years, Queiroz agreed a four-year contract with the Portuguese Football Federation on Friday to succeed new Chelsea boss Luiz Felipe Scolari.
And Ronaldo said: "I have been working with him for some time and I just have to say that he is very good for this job."
Queiroz is believed to have been instrumental in bringing Ronaldo to Old Trafford in 2003, as well as the club's other recruits from Portuguese football, Anderson and Nani, last summer.
He will now manage Ronaldo at international level and whether Queiroz is still as committed to dissuading his star player from moving on remains to be seen.
He told Portuguese broadcaster RTP: "It is with a very heavy heart that I leave the greatest football club in the world.
"This has been a special period in my life both personally and professionally.
"To Sir Alex, I thank him for his faith in me and his knowledge, spirit and desire from which I will take strength and have confidence in my new role."
Ferguson was full of praise for his departing assistant, adding on www.manutd.com: "Carlos is one of the best coaches in world football.
"His attention to detail, ability to innovate and will to win have been a key factor to the team's recent successes. He has played an important role in building and blending the exceptional squad of players at the club."