Ronaldo has claimed three of the last four prizes, having previously seen rival Messi emerge victorious in four successive seasons.
The 32-year-old is also a firm favourite to defend his Ballon d’Or title in 2017, with Madrid legend Hierro hailing his record-breaking achievements in a period of fierce competition from another all-time great.
"Cristiano will be among the best players in Real Madrid history for sure,” Hierro told Goal.
“We will miss him once he leaves. In an era of Barcelona supremacy, in front of Messi, and winning many titles, there's a huge merit in Cristiano winning four Ballons d'Or. Huge!"
The consistency displayed by Ronaldo over recent years stands in stark contrast to the struggles endured by Madrid team-mate Gareth Bale.
While there is no doubting the Welshman’s talent, his inability to steer clear of injury has continued to hamper his progress.
Hierro, though, remains convinced that the 28-year-old can shake off those issues and silence those who continue to question his value.
"Bale will achieve what he wants to achieve, with the ambition he has,” added the ex-Spain international.
“It's true that in his years at Real Madrid there have been too many injuries. But having good physical and technical condition, some day the success will appear. He still has a lot of potential to show.”
Bale is back on the sidelines at present, with his absence allowing others to stake a claim for a starting berth alongside Cristiano Ronaldo and Karim Benzema in the Madrid attack.
Isco is among those to have flourished after being given regular outings by Zinedine Zidane, and Hierro admits that a talent he spotted at a young age has become an almost priceless commodity.
A man who spent 14 years with Madrid in his playing days, added: "I went to La Rioja to watch Isco playing a territorial league when he was 15 years old. After 10 minutes, I left the pitch: it was enough!
"What could Isco's value be in this transfer market? His price would be huge.”
Isco managed 11 goals for Madrid last season and has already added three to his tally this term.
Bale also has three efforts to his name, from nine outings, while Ronaldo is starting to move through the gears following a slow start to the season disrupted by a five-match ban, with his tally taken to seven after netting in his last two appearances.