Former Porsche factory driver Rockenfeller, who set a distance record that still stands on his way to Le Mans victory in 2010 aboard Audi's R15-plus, will race the 2021 Sebring 12 Hour-winning team's newly-delivered car from the 12-14 May Laguna Seca round onwards.
He will share with 19-year-old Dutchman Tijmen van der Helm, who finished fourth in the LMP2 class on his Le Mans debut in 2022 and raced with JDC's LMP3 arm in the opening IMSA rounds of 2023 at Daytona and Sebring.
A third driver for the remaining endurance races at Watkins Glen and Petit Le Mans will be announced at a later date.
“I am excited to be part of this team and the Porsche 963 project!” said Rockenfeller, who will race at Le Mans this year as part of the Garage 56 NASCAR initiative with a Hendrick Motorsports-run Chevrolet Camaro.
“Starting our GTP season at WeatherTech Raceway Laguna Seca for the fourth round of the season is going to be a challenge.
“I am confident the JDC-Miller Motorsports team is on a very steep learning curve and will compete with the GTP teams very quickly.
“So very happy to see my name back on a Porsche.”
Rockenfeller had a short affiliation with the Weissach marque before embarking on 15 seasons with Audi that yielded the 2013 DTM title and 2008 Le Mans Series LMP1 crown.
The 39-year-old won the Nurburgring 24 Hours as part of a factory Manthey Racing line-up in 2006 and won the FIA GT championship's GT2 division with GruppeM Racing the year before.
Team-mate van der Helm said “it does not really matter that we start a bit later in the season” and stated his belief that JDC-Miller “can maximise every opportunity we will get”.
“Going to the Laguna race with a brand-new car will be tough, but I have no doubt that we will be competitive as a team,” he said.
“I look forward to the challenge and opportunity!”
Team boss John Church added that the line-up “represents a balance of youth and experience and features a tremendous amount of on-track success”.
“This pairing combined with the Porsche 963 will allow us to compete for wins in IMSA,” he said.
Porsche achieved its first win with the 963 last time out at Long Beach with Nick Tandy and Mathieu Jaminet's factory Penske-run machine.
Porsche shook down the first customer 963 chassis at its testing facility last week with factory driver Matt Campbell, and both have now been delivered to teams with Jota Sport set to debut its machine in this weekend's Spa World Endurance Championship round.
