The 2018 series is a reboot developed by Peter M. Lenkov and Eric Guggenheim, the same team behind the 2010 reboot of Hawaii Five-0 and the 2016 reboot of MacGyver, and it shares a direct fictional universe with those shows, collectively nicknamed the 'Lenkov-verse'.

The character of Higgins was genderswapped from the original male 'Jonathan Higgins' to Perdita Weeks' Juliet Higgins, a change the creators made deliberately so the reboot could 'stand on its own' compared to the original series.

Tom Selleck, who played the original Thomas Magnum, stated he would never appear in the reboot despite being asked, wanting to avoid overshadowing the original show and citing scheduling conflicts with his own CBS series Blue Bloods.

Several actors from the original 1980s Magnum, P.I., including Larry Manetti and Roger E. Mosley, made guest appearances in the reboot, and Dennis Chun (who had guest-starred on the original as various minor characters) plays HPD Sergeant Duke Lukela in both the reboot and its sister series Hawaii Five-0.

In 2020, Lenkov was fired from CBS following toxic work environment allegations; MacGyver star Lucas Till claimed Lenkov made him suicidal and repeatedly body-shamed him, though Lenkov later issued a public apology accepting responsibility.

Filming takes place on the island of O'ahu in Hawaii, and the fictional Robin's Nest Estate is filmed at Kualoa Ranch, the same location used for Jurassic World.

Each season of filming traditionally began with a Hawaiian blessing ceremony, and the third and fourth seasons required COVID-19 protocols including masks, social distancing, testing, and reduced crew on set.

The production team updated Magnum's signature car from the Ferrari 308 GTS used in the original series (briefly shown in the pilot) to a Ferrari 488 Spider for the reboot.

CBS's cancellation of the series in 2022 after four seasons had a significant negative impact on Hawaii's film industry, leaving an estimated 350–400 people without employment, before NBC picked it up for a two-part fifth season.