The Medellin club confirmed the move on Thursday, hailing the arrival of one of the finest Colombian footballers of all time.
"This isn't an announcement. This is work done out of love for this club. Everyday work, from many people, quietly, so that Nacional keeps getting bigger. When a club works for the club, greatness isn't a slogan: it's a consequence.
"They trusted. They believed. It was inevitable. James Rodriguez is Atletico Nacional," the club said in confirming the deal, before adding: "The greatest to the greatest."
Rodriguez had been without a club since leaving Minnesota United, where he made just eight appearances across MLS and the US Open Cup before departing as a free agent in July. The move was finalised in the hours before the closure of Colombian football's free-agent registration window on Friday. In between, Rodriguez turned down an offer from Italian Serie B side Avellino, whose president had revealed the midfielder's stated intention was to play at the 2028 Copa America.
The 34-year-old returns to Colombian football after nearly two decades abroad, during which he wore the shirts of Real Madrid, Bayern Munich, Porto, Everton and Sao Paulo, among others, in addition to recent spells in Mexico with Leon and in Spain with Rayo Vallecano. His last competitive appearance came on July 7 with the Colombia national team against Switzerland at the World Cup.
Rodriguez first made his name internationally by winning the Golden Boot at the 2014 World Cup in Brazil, a tournament that announced him as one of the standout playmakers of his generation and prompted his big-money move to Real Madrid that same year.
He went on to win the Champions League and LaLiga during his time at the Santiago Bernabeu, later adding a Bundesliga title during a loan spell at Bayern Munich, before a career that carried him through Everton, Qatar, Greece, Brazil and Mexico in its later stages.
Rodriguez's arrival adds him to a growing list of Colombian stars to have joined a Liga BetPlay club in recent years, following Radamel Falcao Garcia, Juan Fernando Quintero, Luis Fernando Muriel and David Ospina — with Juan Guillermo Cuadrado also confirmed as a new Millonarios player on the same day.