While there was one race remaining this season, Schumacher, 19, was second in the second race of the day on the German Hockenheim circuit, leaving him with an unassailable lead in the championship. drivers.
"It's not really gone back into the water yet," Schumacher said.
"I am delighted, the team has accomplished a lot throughout the year."
Schumacher had been a picture of concentration in the final laps to rank second and secure the title, but he hit the air after crossing the finish line.
"In fact, an error I made earlier in the race has bothered me," he said with a smile.
Estonians Juri Vips took the checkered flag, but all the attention went to Schumacher, who dominated the second half of the F3 season after winning five consecutive victories last month.
He embraced his team after finishing on the podium for the 13th time in 29 races this season.
Before the last race Sunday, Schumacher totaled 347 points, 51 more than the British Daniel Ticktum, second in the standings and only driver to have managed to take the German.
Schumacher finished 12th Saturday morning after a premature crash forcing him into the pits, but did not make any mistakes of this type in the second race of the day.
His first title in F3 means that Schumacher has qualified for a "super license" from the FIA, prior to the switch to Formula 1, and succeeds his father, who won the German F3 championships there 28 years.
The presence of the German teenager with the famous name has sparked a strong media interest for the F3 this season.
After a mediocre start, things clicked in July, when he won at Spa in Belgium, to clinch his first win in the 15th of 30 races of the season.
He then started a series of nine podiums in the next 12 races.
In September, he won five consecutive wins, three on the German Nürburgring, followed by the first two on the Austrian Spielberg circuit, to take control of the drivers' championship.
Born in March 1999, the year before the year his father won the first of five consecutive world titles in Ferrari, Mick began his career in karting at the age of nine.
To avoid any attention, he ran under the name "Mick Betsch", using the maiden name of his mother Corinna.
He was on the track with his father in December 2013 when an accident in the French ski resort of Méribel had left Michael Schumacher badly injured in the head.
The 49-year-old has not been seen in public since he's recovering from his injuries at home in Switzerland.
In 2014, Mick Junior finished the karting season in second place at the German, European and World Championships.
Finally under the family name, he climbed to F4 in 2015.
Schumacher scored his first victory at Oschersleben for Van Amersfoort Racing, but finished tenth overall with only two places on the podium.
The young Schumacher still being in the spotlight, Sabine Kehm, the head of his father, fiercely shelved the questions of journalists.
In 2016, Schumacher Junior finished second in the German and Italian F4 Championships. Last year, when he reached the F3 Championship, he was 12th with only one podium.
This season it has been a revelation for Prema Theodore Racing, leaving it speculating that he would race in Formula 2 next season – or that he would sneak right into F1.