The towering centre-back had been without a club since leaving Leicester in the summer, when the two parties agreed to terminate his contract after almost five years at the King Power Stadium.
Vestergaard joined Leicester from Southampton in August 2021 and went on to make 118 appearances for the club. He was part of the side that won the Championship title in 2023/24 before Leicester endured back-to-back relegations.
The defender made 31 Championship appearances last season, scoring three goals, before leaving the club.
Now, after weighing up whether to continue, Vestergaard has decided that his playing career is over.
“A feeling of weariness has crept in,” he told Politiken. “It feels right to stop now.”
He explained that his motivation had gradually disappeared rather than simply declining.
“A feeling that the motivation is not only weakening, but actually isn't there anymore. It feels right to stop now.”
Vestergaard had already announced his retirement from international football earlier this year, bringing an end to a Denmark career that produced 59 caps and three goals.
His club career began in Germany with Hoffenheim before spells at Werder Bremen and Borussia Mönchengladbach. He subsequently moved to England, joining Southampton before Leicester.
The 34-year-old leaves the game having made 100 Premier League appearances, scoring four goals. He also played 185 Bundesliga matches and scored 14 times.
Leicester confirmed in July that Vestergaard's contract had been terminated by mutual agreement, ending his time at the club after 118 appearances.
His decision now closes a career that took him from Danish football into Germany's Bundesliga and then the Premier League, while also establishing him as a regular part of Denmark's international set-up.
Vestergaard's final decision was driven by motivation rather than a lack of options. After stepping away from the national team and leaving Leicester, he has now decided there is no desire to begin another chapter at club level.