Dempsey, the Firestone Freedom 100 winner who is fifth in the Firestone Indy Lights championship standings, will drive the No. 2 TMR/Global Tubing/ALS Association car in the Oct. 5 race on the 1.683-mile, 10-turn street circuit.
"I could not be happier to be joining Team Moore Racing for the Houston race," said Dempsey, of Ireland. "TMR, Mark Moore, and Tom Wood are proven multiple race winners in the Firestone Indy Lights series and I am heading to Houston with great confidence that I am surrounded by the right people.
"I'm also really looking forward to having Conor Daly as my teammate for the weekend. We are friends off the track and competitors on the track, so I think we will work really well together and hopefully be in the position to reward TMR with the results they deserve."
Team Moore Racing announced last week that Daly, a former Firestone Indy Lights race winner and current GP3 driver who also made his IZOD IndyCar Series debut in the Indianapolis 500 in May, would drive the No. 22 entry at Houston.
Dempsey recorded the victory at Indianapolis Motor Speedway in May along five other top-five finishes in 10 races for Belardi Auto Racing, which announced last week it didn't have sufficient sponsorship to field the No. 5 car in the final two races.
"Team Moore Racing is giving me the opportunity to keep my title fight alive, and for that, I will always be thankful," Dempsey added. "I'd really like to thank all of my team sponsors along with my personal sponsors for making this all come together."