Fernandez also revealed he had received a number of recommendations about the Welsh club, including one by Spanish striker Michu, who is currently on loan at Napoli from Swansea.
The Swans stated on their website that Fernandez has signed for an undisclosed fee, subject to international clearance.
The 25-year-old passed a medical earlier this week, and is expected to be in Swansea's squad for their league game against Burnley at the Liberty Stadium on Saturday, when manager Garry Monk will look to build on last weekend's 2-1 win at Manchester United.
Fernandez's arrival at Swansea from Napoli will bolster Monk's centre-back options, which currently include captain Ashley Williams, Jordi Amat and Kyle Bartley.
"I t has alwa ys been my dream to play in the Premier League - it is the best in the world - and I'm grateful to Swansea for giving me this opportunity," Fernandez told the club's official website
"I asked Michu and Jordi Amat about the club
I obviously trained with Michu at Napoli, and while I was on loan at Getafe (in 2013) I played with (former Swansea loan player) Alvaro Vazquez
He is very good friends with Jordi, so I've spoken to them too
"Michu told me it is a family club and the city is very relaxed
He said I was joining a very good club
All I've heard are good things about Swansea."
Fernandez has won 26 caps for Argentina, including making four appearances at the World Cup in Brazil earlier this summer
He made his international debut against Ecuador three years ago, while his first World Cup finals appearance came during the 2-1 victory over Bosnia and Herzegovina in Rio de Janeiro.
He joined Napoli in 2011 from Estudiantes for around £2.5million, helping them land the Coppa Italia last season during a campaign when they also finished third in Serie A.
Fernandez additionally featured in Napoli's Champions League and Europa League campaigns, although he was not involved in either leg of the Europa League last-32 tie against Swansea.
"I can identify myself with the Swansea style
I like to play the ball from the back and, of course, I love to defend too," Fernandez added
"I was impressed last weekend with the team's performance and result against Manchester United.
"It was a very intelligent performance
The team really took its opportunities, and it was a fantastic start to the season.
"I just can't wait to start training and playing games."
Source : PA
Source: PA