It's a dramedy about a family in crisis mode, with members dealing with pregnancy, divorce, bankruptcy and now a brain tumor.
For Krasinski, the film also represented a chance to reunite with his costar from his first-ever acting job. That was a commercial for Marshall's.
"I was an extra," Krasinski recalled. "I got bumped up to featured extra which means you get to interact with the lead in the commercial. And that lead was Margo Martindale. So this is a big full circle for me."
In the film, Martindale plays his mother, who learns she has a brain tumor.
"I think this script is so specific and honest and a true take on family," Krasinski said. "So when I decided to direct it, the first call I made was to Margo Martindale. And to be honest, had she said no, I don't know that I would have directed it."
The film co-stars Anna Kendrick as Krasinski's pregnant girlfriend, Richard Jenkins as his father and Charlie Day as Martindale's nurse.
Krasinksi credits his cast with helping him get this movie made in just 22 days.
"This was a small budget movie and a movie made out of love," he said. "I will say it would have taken me 22 years to make this if I didn't have actors who understood tone and honest performances like this."
The PG-13 film, which runs just about 90 minutes, opens in theaters Friday.