Cortese plays one of five 30-somethings who share their relationship troubles during a weekly pub quiz night in the new TV One drama.
The show also stars Tandi Wright, from This Is Not My Life, and Go Girls' Blair Strang.
Cortese, who made his name in Shortland Street and Outrageous Fortune, says he is relishing the weightier drama role.
"All of those other characters had a quirkiness. This is a very different role.
"It's the most challenging role I have had to play because he is such a real life character. It's a real challenge to play someone who is pretty similar to yourself."
Outrageous Fortune's Nicole Whippy and Debbie Newby-Ward, from The Pretender, also star in the series, and Cortese said it helped that the cast members were already friends.
"Technically, it's a very difficult show. It wasn't really a show conducive to newcomers. We are a pretty tight group."
Writer Rachel Lang, co-creator of Outrageous Fortune and Go Girls, said she enjoyed writing about characters closer to her age group.
"The characters find comfort in answering the small questions, even if they can't answer the big questions," Lang (50) said.
The show, the latest to come off the highly successful production line at South Pacific Pictures, is described as funny, warm and romantic.
Life centres around the weekly pub quiz at the fictitious Beagle pub where the friends confide in each other while trying to win the bar tab.
• Nothing Trivial screens Wednesdays at 8.30pm on ONE.
