The run took place in the Danish cities of Aalborg, Aarhus, Esbjerg, Odense and Copenhagen with around 70,000 participants – and Frederik challenged himself to run in each of the five cities.
Speaking prior to the event, Frederik said his aim was to ‘bring joy, well-being and energy’ while encouraging people to take part in physical activities.
‘When I turn 50-year-old, I will celebrate the day with a race where all of Denmark can join…’ he said previously.
‘A run must be a race aimed at the experienced runners, but equally to those who tie their running shoes for the first time and everyone is welcome regardless of age…Will you join?’
Taking to the Royals’ official Instagram page on Monday evening, Frederik thanked those who had joined him on the run.
‘My running shows have been around Denmark’s five biggest cities today,’ he wrote.
‘Thank you for a touching and fantastic day.
‘My desire to gather the Danes… is fulfilled. In every city I have met happy people who have challenged themselves and achieved personal victories.
‘Thank you so much. #RoyalRun’
Earlier in the day – after completing runs in four cities - he had posted a picture from a helicopter as he travelled to Copenhagen for his final stint.
Frederik and Mary appeared in good spirits during the day – with the princess pictured laughing heartily during the fun occasion.