Kenny Dalglish

 Kenny Dalglish is the only person to win England's top flight as player-manager.

Following Joe Fagan's retirement in 1985, Dalglish became Liverpool's manager while still playing for the club.
He selected himself for 21 First Division games in the 1985-86 season, which Liverpool won.
In the 1987-88 and 1989-90 seasons, where Liverpool won their 17th and 18th league titles respectively, Dalglish was also player-manager but played very few games, as he was already approaching 40.