The 42-year-old, who played for Spanish giants Real Madrid and Barcelona during an 18-year career, said his immediate aim was consolidating the club’s top-flight status.
Valladolid were promoted this season and have two points from their opening three games.
'They underestimated me' - Suarez hits back at Barca after Atleti title win
23/05/2021 AT 11:20
"We want Real Valladolid to consolidate in the top flight and keep building hopes from there," said Ronaldo.
"It will not stop there because we want to grow to where our hopes allow us to."
Carlos Suarez, who Ronaldo purchased his stake from, will continue as club president.
"The arrival of Ronaldo puts Valladolid on the map and will allow the club to take a leap forward in quality. I welcome him to his home," said Suarez.
Imperfect champions of an imperfect title race, Atleti and Suarez deserve their glory
22/05/2021 AT 19:05
Atletico champions as Suarez seals comeback victory at Valladolid
22/05/2021 AT 15:19