Robertson ended the 2018-19 campaign in possession of a Champions League winner's medal and the Premier League's best defensive record with just 22 goals conceded.
The Scot and teammate Trent Alexander-Arnold also made history as their combined 23 assists in the Premier League was the first time two defenders from the same team have each registered double-digit tallies in a single season.
"I think I've been good but I can always be better," the 25-year-old said. "That's the way I've always worked.
"I'll never praise myself because I think there's always improvement to be made.