The Norway international became Ole Gunnar Solskjaer's first signing as Cardiff boss when he completed his move from Heerenveen for a fee believed to be in the region of £2million.
Eikrem, 23, spent five years at Manchester United without making a first-team appearance, although he did work with Solskjaer when the former striker was in charge of the reserve side at Old Trafford.
The midfielder looks set to finally make his Premier League debut against West Ham on Saturday, although he is likely to be named as a substitute.
And the former Molde player admitted he took little persuading to swap the Eredivisie for a return to English football.
He said: "It was an easy decision when I head Heerenveen had got an offer from Cardiff. It was a no-brainer really and I went as fast as I could.
"The lads are great, they have taken good care of me, training has been really good and it is really a step up for me."
Solskjaer enjoyed a successful spell in charge of Molde after leaving United, winning two league titles and a cup with the Norwegian club.
Eikrem was part of the two league successes and was more than happy to again link up with Solskjaer in south Wales.
He said: "I saw what type of manager he was at Molde.
"We started off really badly in the league but we ended up taking the Cup (after Eikrem had left).
"The focus was the same all the time, it was about getting us playing again and getting everyone excited to play.
"When we were struggling at the bottom of the table he just said how good players we were and just continue how we did last year."