Askou has won promotion to the Danish top flight with both Vendsyssel and Horsens. In between those jobs he won a league and cup double in the Faroe Islands with HB Torshavn.
In June 2023, he took over at IFK Goteborg for a year before joining Sparta Prague as an assistant coach.
In January, he took up a similar post at FC Copenhagen working under manager Jacob Neestrup.
"We had a high number of impressive applicants, but we were really drawn to Jens," said Motherwell chairman Kyrk Macmillan.
"His track record of working with big clubs, delivering success and developing young players matches up with all our philosophies.
"He has handed 26 teenagers debuts in five-and-a-half seasons, which I think is evidence of Jens implementing his ideas and morals.
"The data and numbers impressed us, but more importantly, after speaking with Jens a number of times, he is a really ambitious character and a leader who was extremely keen to get the role here at our club."
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