Details of Harte's contract are to be announced at the press conference. His departure from Leeds United - his single English club since 1995 - marks another departure from Elland Road, following in the footsteps of Alan Smith, Paul Robinson, James Millner, Dominic Matteo and Mark Viduka, most recently, in a mass exodus.
Levante will be competing in the top flight of the Spanish league for the first time in 39 years, and last week completed the signing of Swedish defender Johan Mjallby from Celtic.
Harte has struggled to feature in Republic of Ireland boss Brian Kerr's plans, losing ground on Manchester United's John O'Shea due to injury and lack of form. He earned his last international cap in the April 28 0-0 draw with Poland in Bydgoszcz.
The talented left-back has hit nine international goals in his career, three of those coming in the 2002 World Cup qualifiers.