The play casts Mr. Hall and Lindsay Crouse as doctors reflecting on a pharmaceutical trial in which its two research volunteers have fallen in love. The production, which runs through July 8, brought Mr. Hall to the seaside city of Gloucester, Mass., to work with his co-stars and the play’s director, Sam Weisman, a frequent collaborator. “Whenever we were on a soundstage together and something would go wrong,” Mr. Hall said, “we’d look at each other and go, ‘It won’t be like this when we go back to the theater.’ So we’re testing that premise.”
Mr. Hall has continued to act on shows like “Parks and Recreation” and “Brooklyn Nine-Nine,” and to direct episodes of Ms. Louis-Dreyfus’s HBO satire, “Veep.” Still, he said that an occasional gig outside the geographical boundaries and critical pressures of the entertainment industry was a crucial change of pace.
When he is working on a TV assignment, Mr. Hall said: “You have to run, an awful lot, on instinct. Even on ‘Veep,’ it’s not like you get weeks of rehearsal to break out what’s going on in the scenes.”
With “The Effect,” he said, “It’s nice to be able to sit down and have a discussion about something for more than four minutes, and not look at your watch and go, ‘Oh my God, I just spent $40,000 of HBO’s money.’”
Given how much theater he did at Northwestern University (where the Practical Theater Company was created as Attack Theater) and in the years after, Mr. Hall said it was bittersweet to have drifted away from the stage and then returned to it. “It’s part of my DNA,” he said. “To step back into it, it’s both brand new and nostalgic at the same time. That’s exactly what I hoped it would be.”
Among his future projects, Mr. Hall has created a new TV series, “Picture Paris,” starring Meg Ryan and adapted from a 2011 short film he wrote and directed. But the galvanic response he gets from…