The season expanded to fourteen rounds, the largest calendar in the championship's recent history. The FIA introduced a permanent driver numbering system similar to those used in Formula 1 and MotoGP, replacing the previous arrangement in which numbers reflected the prior season's manufacturers' standings. The maximum total distance of competitive special stages per event was reduced from 500 kilometres to 350 kilometres. WRC3 was discontinued and a new WRC2 Pro class was created for manufacturer-supported entries running Group R5 cars, sitting between the WRC2 open class and the full World Rally Car entries.
All four manufacturer teams — Citroën, M-Sport Ford, Hyundai, and Toyota — used Michelin tyres. Citroën scaled back to two full-time entries. M-Sport Ford similarly reduced to two full-time cars. Toyota expanded to four cars, running an additional entry under the GRX Team banner for Marcus Grönholm. Hyundai retained their three-car lineup and brought Sébastien Loeb in for a six-round programme.
Sébastien Ogier, returning to Citroën after his time at M-Sport Ford, and Thierry Neuville of Hyundai entered the season as the two favourites, but Ott Tänak of Toyota emerged as the dominant force across the calendar. Tänak won the Rally Sweden — his first snow rally victory — and followed it with further wins in Portugal, Finland, Germany, and Wales. His victory in Wales extended his championship lead to twenty-eight points with two rounds remaining.
Tänak clinched the title in Spain at the RACC Rally Catalunya, where a dominant power stage victory gave him second place overall and an unassailable lead over Neuville. His title was secured without needing to win the final round. Tänak and co-driver Martin Järveoja finished thirty-six points clear of Neuville and Nicolas Gilsoul at the season's conclusion. Ogier and Julien Ingrassia finished third.
In the manufacturers' championship, Hyundai Shell Mobis WRT claimed their first manufacturers' title, defeating defending champions Toyota Gazoo Racing WRT. Citroën Total WRT finished third and subsequently announced their withdrawal from the WRC at the end of the season.
The Rallye Automobile Monte Carlo opened with a three-way battle among Ogier, Neuville, and Tänak, with Ogier winning for a sixth consecutive year in Monaco. Rally Sweden saw Tänak sweep to victory after Ogier and Latvala hit snowbanks on the opening leg. At Tour de Corse, Neuville won despite Tänak suffering a puncture that cost him the lead; the result moved Neuville to the top of the standings.
At Rally Argentina, Neuville drove cleanly while multiple rivals retired, taking victory. The brand-new Rally Chile — the first South American gravel rally outside Argentina on the WRC calendar — was won by Tänak despite Neuville's dramatic high-speed crash that temporarily opened the championship to others.
Rally Finland saw Tänak comfortably defend his home-country event, recording his 200th WRC stage win during the weekend. At Rallye Deutschland, Tänak completed a hat-trick of wins on German tarmac as Neuville suffered a puncture on the longest Panzerplatte stage. Ogier took victory in Turkey when both Tänak and Neuville encountered problems. The season's final scheduled round, Rally Australia, was cancelled due to bushfires in New South Wales, meaning Hyundai clinched the manufacturers' title without the event being held.
Tänak's 2019 title ended fifteen consecutive years of the drivers' championship being won by either Sébastien Ogier or Sébastien Loeb. His victory represented both Toyota's first drivers' title since 1999 and the first championship for an Estonian competitor in any FIA world championship. Tänak's driving style — aggressive, consistent on all surfaces, and particularly dominant on gravel — and his willingness to score power stage bonus points throughout the season were defining features of his campaign. He finished the year with six outright rally wins, the most of any driver that season.