The ex-midfielder, who lifted the European Cup twice with Nottingham Forest, died on Monday in Marbella.
"Trevor Francis has died at the age of 69. He had a heart attack at his apartment in Spain this morning," his family said in a statement.
"On behalf of the family, this has come as a huge shock to everybody. We are all very upset. He was a legendary footballer but he was also an extremely nice person."
Francis began his career with Birmingham City but made history when he signed for Nottingham Forest in 1979 for over £1 million, the first player to move for such a fee which was a British record at the time.
The move saw Francis win back-to-back European Cups with Brian Clough's legendary Nottingham Forest side, scoring the winner in the final win over Malmo in 1979.
Francis subsequently signed for Manchester City in 1981. He then enjoyed spells abroad with Sampdoria and Atalanta, before returning to the United Kingdom and finishing his career with Rangers, QPR and Sheffield Wednesday.
The former midfielder also won 52 caps for England during his playing career. Former England team-mate Gary Lineker paid tribute to Francis on social media.
"Deeply saddened to hear that Trevor Francis has died," he tweeted. "A wonderful footballer and lovely man. Was a pleasure to work alongside him both on the pitch and on the telly. RIP Trevor."
Francis moved into management after hanging up his boots, reaching the finals of the FA Cup and League Cup with Sheffield Wednesday and also guiding Birmingham City to a League Cup final during his time in charge.