The 27-year-old has signed a contract running until the summer of 2031, with Atletico Madrid paying a fee reported at €40million plus a further €5million in add-ons, comfortably below the €80million release clause written into his previous contract.
Fabrizio Romano had confirmed a full agreement between Atletico, Sporting and the player earlier in the week, before Atletico's official announcement made the move formal. Hjulmand had also been strongly linked with Arsenal, Manchester City and Milan in recent months, but his career instead continues in Spain.
Hjulmand leaves Sporting having made 141 appearances in three seasons since joining from Lecce in 2023, scoring 10 goals and adding 12 assists, and lifting two Liga Portugal titles and a Taca de Portugal as captain. Last season he scored three goals and added four assists in 27 Liga Portugal appearances, 26 of them starts, while also winning 27 caps for Denmark. Sporting finished fourth last season.
Speaking to Atletico's official media after putting pen to paper, Hjulmand said he could hardly wait to get started.
"It's a very big club," he said. "I've been watching it from a distance since I was a kid, always winning trophies in Spain and in Europe. It's a club that's very respected in Europe and deserves to be.
"It's an honour to be part of it. It means a lot to me, because being part of Atleti is a dream come true."
Asked how he was feeling, Hjulmand admitted to a mix of excitement and nerves.
"I'm very excited and also nervous, as always happens when you arrive somewhere new, but I think I'll adapt easily from what I've heard about the players. I'm really looking forward to meeting them and learning the language as quickly as possible. I can't wait to start training on Monday."
On what he can offer Diego Simeone's side on the pitch, Hjulmand explained: "I think I bring balance to a team. I try to balance defence and attack. I'm very communicative with my body language and my voice to help the team. I'm like that in training and when we're together before and after matches. During matches I think I can bring these qualities to Atleti."
The Dane also reflected on how his leadership qualities have developed, from his early days in Austria through to the Sporting captaincy.
"At 17 or 18, my coach gave me a bigger role with more responsibilities," he said. "When I went to Austria I was very young and I made a lot of mistakes with the more experienced players, especially with my communication and my character, but I learned a lot from them. Also at Lecce, where I was lucky enough to be captain, and at Sporting, which has been a privilege to captain."
Hjulmand also spoke about his first impressions of the Metropolitano and the atmosphere awaiting him once the season begins.
"I came to the stadium for the first time this morning. I was surprised by how big it is. But I can't imagine what the atmosphere will be like with 70,000 people there. I've watched matches on television and you can hear the fans, so I think it'll be crazy during the season when we play in the Champions League and in LaLiga."