In his acceptance speech, Platini pledged his love for FIFA despite supporting all three candidates against Blatter in the world governing body's own presidential election.
Platini ran unopposed to extend his reign, which started in 2007, and was voted in by acclamation by the leaders of UEFA's 54 member federations to serve four more years.
"This means more to me than you could possible imagine," Platini said in an acceptance speech in French.
Platini also retained his position as a FIFA vice-president through 2019.
The former France great will be joined on the FIFA executive committee by former Manchester United CEO David Gill and Germany football federation president Wolfgang Niersbach. Both previously said Blatter should leave FIFA this year.
Though Platini opted not to stand against Blatter in the FIFA election on May 29, UEFA backs all three other candidates.
"We love FIFA deeply," Platini said, watched by Blatter sitting at the front of the congress hall. "It is entirely because we love and respect FIFA that we want it to be perfect.
"We Europeans want a strong FIFA, a FIFA that is respectable and respected," Platini added, before taking an apparent jibe at his onetime mentor.
Platini said some people wanted to isolate UEFA as "arrogant and selfish."
"Certain people are perhaps trying to turn us against each other, seeking to divide and rule," Platini said in comments directed to other confederation leaders attending as UEFA guests. "Don't believe everything you hear. We know that we make mistakes and are not necessarily any better than anyone else."
Platini pledged that Europe would continue to work with FIFA and other continents "whatever the result on the 29th of May."
FIFA presidential candidates Michael van Praag of the Netherlands, Luis Figo of Portugal and Prince Ali bin al-Hussein of Jordan were scheduled to give campaign speeches to delegates later Tuesday.
Blatter, who was expected to stay and watch his rivals, declined UEFA's invitation to also speak on stage. He has also rejected requests from British and Dutch broadcasters to take part in a separate debate.
In other elections by UEFA delegates, Gill defeated Trefor Lloyd Hughes of Wales to win the FIFA vice presidency reserved for British nations.
Niersbach was unopposed for a vacant seat at FIFA, and Angel Maria Villar of Spain had no rivals to retain a FIFA vice presidency for four more years. Villar was a candidate while under investigation by the FIFA ethics committee for his conduct during the 2018-2022 World Cup bidding contests and subsequent probe.
Seven men were elected to the UEFA executive committee: former Croatia forward Davor Suker, Portuguese sports official Fernando Gomes and Hungarian banker Sandor Csanyi won seats for the first time. All are national federation presidents.
Villar, Peter Gillieron of Switzerland, Borislav Mihaylov of Bulgaria and Hrigoriy Surkis of Ukraine got renewed four-year mandates.Suggest a correction