The 31-year-old amassed more than150 matches in the Danish Superliga as well as the Bundesliga and 2. Bundesliga. He most recently played with Malaysian Super League outfit Penang.
Reds coach, Marco Kurz, praised the acquisition of versatile forward who describes himself as a "very direct" player.
“Ken is a very good player and someone with a lot of offensive abilities," Kurz said. “I have known of Ken for a few years while he was playing in Germany and have always been impressed with his quality. 

“In the last few seasons Ken has been playing in Asia and has scored a lot of goals and made a lot of assists. 
“Not only can he play as a striker, but he can also play as a creative midfielder behind the striker as well and this versatility is very good for any football team. 

“These are things that we need and I am confident that Ken can bring this to our team for the new A-League season, but also the FFA Cup, which will start very soon.” 

Ilsø began his career in the Dutch Eredivisie before returning to his homeland to play for SønderjyskE and then FC Midtjylland. 

A successful spell in Denmark secured a move to German second division side Fortuna Düsseldorf midway through the 2010/11 campaign and in his first full season he helped gain promotion to the top-flight for the 2012/13 season.

The former youth international, has been on the books of VfL Bochum, as well as Home United of Singapore and Malaysian team, Kedah. The Dane enjoyed a prolific goal-scoring record in Southeast Asia, bagging a total of 61 goals in 85 matches in all competitions with Home and Kedah.

Ilsø said he was looking forward to the new challenge.
“I’m really excited to join Adelaide United and about the upcoming season,” Ilsø said. “I’ve always wanted to play in Australia somehow, at some point in my career, and I’ve been trying for at least the last two years to see if it could be possible.

“Then Marco came here and did a very good job last year and now I got the chance and I’m not going to let that chance run.

“I’m here and I want to make the new season better than what the team was able to achieve last season and I want to reach a high amount of goals, creating a lot of chances for my teammates too.

“Adelaide United fans can expect from me a very direct player who’s always looking to create opportunities and then always trying to go for goal.”