Fourth seed Djokovic raced through the first set without dropping a game and although he was made to work harder in the second, still won in a little over an hour and 20 minutes.
The Serb, who received a bye in round one, will face world number 69 Camilo Ugo Carabelli of Argentina in the next round.
Build-up to the tournament has been dominated by news that the Professional Tennis Players' Association (PTPA), co-founded by Djokovic, has begun legal action against tennis' governing bodies.
However, in his first match in Miami since 2019, the 37-year-old showed no signs of being distracted as Hijikata was swiftly swatted aside.
The 24-time Grand Slam champion broke in the second game of the match and never looked back, winning the first set to love in 28 minutes.
It was more of a contest in the second, but Djokovic dominated in the tie-break to move a step closer to a seventh Miami Open title.