David Moyes described La Liga as "better than the Premier League" at his unveiling as Real Sociedad manager.
Moyes, 51, who was sacked by Manchester United in April, said he took charge of the Spanish side after turning down offers from clubs in the Premier League.
"Real Sociedad tugged at my heart strings," Moyes said.
"La Liga has the finest players and great coaches and I want to test myself against the best."
He added: "It is the right time. I am well rested and I am ready to go."
Moyes has signed a contract to June 2016 and replaces Jagoba Arrasate, who was dismissed after a poor run of form which has left the club 15th in La Liga.
There are reasons for optimism, however. Sociedad have already beaten Real Madrid this season and recorded their second win of the campaign on Sunday when they overcame champions Atletico Madrid.
"This is the best league in the world, in my opinion," Moyes, who will take charge for the first time at Deportivo on 22 November, added at his presentation in San Sebastian.
"I see great morale amongst the players - last Sunday's result against Atletico really lifted them. My job is to extract the best of them and make them competitive.
"I feel this job fits my character. It's been a big decision for me and my family."
Real Sociedad's next five games
22 November: Deportivo (a)
29 November: Elche (h)
4 December: Oviedo (a) - Copa del Rey
7 December: Villarreal (a)
14 December: Athletic Bilbao (h)
Moyes, who is Sociedad's fourth British manager after Harry Lowe, John Toshack and Chris Coleman, hinted that he will allowed to dip into the transfer market in January if he deems it necessary.
"I have to assess the players I have here," he said. "The transfer window is five weeks away. The president said he will do everything he can to help me."
The former Preston and Everton manager succeeded Sir Alex Ferguson at United in July 2013 but was was sacked four games from the end of last season with the club lying seventh in the Premier League.
Moyes hopes his return to management after six months away from the game will deliver results to rival his time at Goodison Park.
"I had a great 11 years at Everton, a club very similar to this," Moyes said. "I took over Everton and grew it and it got better and better. I am hoping I can do the same here."Moyes was presented by Real Sociedad president Jokin Aperribay (centre) and director general Lorenzo Juarros (left)