The 57-year-old, who spent several months at Loftus Road as first-team coach in 2013, was announced as Ian Holloway's successor just weeks after the end of the 2017-18 season.
Some fans criticised Holloway's departure and McClaren's appointment, but Fernandes insists that the recruitment process was "the most extensive" ever carried out by the club.
"Steve always impressed me from the moment I met him when Harry Redknapp brought him in as a helping hand," Fernandes told the official QPR website.
"I liked the way he got involved with individual players' training, such as Junior Hoilett, I noticed that in pre-season especially.
"When Steve left us there was a notable change in the squad. We were unbeaten up until that point, I tried to keep him and we kept in contact.
"We did an extensive search - probably the most extensive we've ever done and met many, many managers and everyone was suitably impressed with Steve."
McClaren's last two English roles, at Newcastle United and Derby County respectively, lasted a combined total of 60 matches.