Villar, the RFEF president, has been acting head of UEFA since October 2015, when Michel Platini was suspended from all football-related activities.
Villar's rivals include Aleksandar Ceferin, Slovenia's football boss, who has claimed to have support from almost one third of UEFA's member associations.
Dutchman Michael van Praag is also a candidate in the Sept. 14 election to replace Platini, who has been banned from football for four years for ethics violations.
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Villar is a former midfielder for Athletic Bilbao and a Spain international. He was one of the founding members of the Spanish Footballers' Association (AFE).
He was elected president of the RFEF in 1988, winning seven consecutive elections, most recently in 2012.
Villar is also a vice-president of FIFA. Last year he was fined 25,000 Swiss francs by the organisation's Ethics Committee for failing to cooperate with their investigation into the contest to host the 2018 and 2022 World Cups.
Villar presided over the most successful era in the history of the Spanish national team, who won successive European Championships in 2008 and 2012 and the World Cup in 2010.
Despite those successes, Villar divides opinion in Spanish football.
Javier Tebas, the president of La Liga, has publicly criticised Villar on numerous occasions for his leadership of the RFEF.
Their relationship came under strain in 2015 when Villar supported a planned strike by players against a new law regulating the collective bargaining for the sale of television rights. Tebas lobbied for the new ruling.
The pair also clashed in 2014 over how to solve the problem of violence in Spanish soccer, Tebas criticising Villar's decision to not attend a crisis meeting after a fan was killed before a game between Deportivo La Coruna and Atletico Madrid.
Tebas sarcastically said in May that he would back Villar's bid for the UEFA presidency. "It could be very good if Angel Maria Villar would dedicate himself exclusively to Europe and someone else lead Spanish football," he said.
Villar has also come in for criticism from RFEF general secretary Jorge Perez, who is standing to succeed him as president and recently accused Villar of horse-trading for political gain.
"I won't say that he hasn't done many good things, because he has, but this model is finished," Perez told newspaper AS on Tuesday.
(Reporting by Richard Martin; Editing by Toby Davis)
