The Real Madrid and Croatia midfielder starred for both club and country as Madrid won a third straight Champions League, and he inspired Croatia to reach the World Cup final for the first time.
He beat Ronaldo and Liverpool’s Egyptian forward Mohamed Salah to the prize.
Modric’s success means Ronaldo remains tied with Messi having won FIFA’s award in different guises five times each.
At 33, Croatia’s run to the final was the culmination of a brilliant career for Modric that had often been overshadowed by Ronaldo’s goalscoring in their time together in the Spanish capital, before the Portuguese left for Juventus in July.
Modric scored twice and also netted in penalty shootout wins over Denmark and Russia, but it was his playmaking ability that caught the eye in winning the Golden Ball for the best player at the World Cup.
“It was an unbelievable season, the best season in my life,” said Modric.
“I’m still not realising how good a year I had collectively, individually, and I’m very proud for everything I achieved this year and it will be remembered forever.”
For a sixth straight season, Ronaldo was the Champions League’s top scorer with 15 goals and also scored four times at the World Cup, including a hat-trick against Spain in a thrilling 3-3 draw to open Portugal’s campaign.
However, Portugal’s last 16 exit to Uruguay in Russia and Ronaldo’s failure to score in the semi-finals or final of the Champions League opened the door for Modric.
Neither Ronaldo or Messi attended the glitzy ceremony in London with both in action for Juventus and Barcelona respectively on Wednesday.
For the first time in 12 years, Messi was not among the finalists with third place going to Salah for his incredible 44-goal debut season with Liverpool that carried the Reds to the Champions League final.
However, a shoulder injury suffered early on in the final robbed Salah of the chance to help Liverpool lift the trophy and also meant he was far from peak condition as he led Egypt’s World Cup bid.
Despite scoring in each of his two appearances in Russia, he bowed out with the Pharaohs bowed at the group stage with three defeats.
Salah did not go away empty handed, however, as he picked up the Puskas award for best goal for his strike against Everton in the Merseyside derby last December.
Modric was joined by Real team-mates Sergio Ramos, Raphael Varane and Marcelo in the FIFPro team of the year, also featuring David De Gea, Dani Alves, N’Golo Kante, Eden Hazard, Kylian Mbappe, Messi and Ronaldo.
France’s World Cup-winning coach Didier Deschamps won the best coach of the year prize in recognition for his work in leading Les Bleus to success in Russia.
Deschamps, who became just the third man to win the World Cup as a player and coach, beat off competition from Dalic and his former France team-mate Zinedine Zidane, who won a third consecutive Champions League title with Real Madrid before resigning in June.
Thibaut Courtois won the best goalkeeper award for helping Belgium reach the World Cup semi-finals as well as the FA Cup with Chelsea before a summer move to Madrid.
Brazil’s Marta was crowned best women’s player for a record sixth time for her role in winning the Copa America to beat out Lyon duo Ada Hegerberg and Dzsenifer Marozsan.
Lyon boss Reynald Pedros did win the award for best women’s coach, though, after winning the Champions League with the French giants.