After being a series regular on TV3's comedy panel shows 7 Days and Would I Lie To You?, he describes the change of networks as "momentous" and is chuffed about getting the role as resident jester on Seven Sharp.
"This sort of opportunity comes up once in a lifetime," he says of the prime-time slot and demanding daily turnaround of the show.
The 37-year-old ponders how getting the job makes worthwhile the tireless trips he used to do from his home town of Hamilton to Auckland in his mum's car every week in the mid-90s for a 10-minute stand-up slot at an Irish pub.
"When you start out in comedy you agonise over every word, but all that practice makes you much more intuitive."
It's not that Mulligan is naturally funny, like some of his 7 Days contemporaries, such as team captain Paul Ego and host Jeremy Corbett, but he is quick, clever and, when the time is right, cutting. And it's telling that his more considered comedy approach, which came through in his 2010 comedy festival show Middle Class about being a new dad, made him more of a natural choice for Seven Sharp than his other 7 Days team-mates.
"I'm probably a wordy guy," he says, which is why many of his favourite comedians are the highly verbal likes of Jerry Seinfeld and Woody Allen, and he's also a fan of fearsome British restaurant critic A. A. Gill.
In person Mulligan's a likeable chap, and seemingly not the self-promoting type who just wants to get his mug seen and voice heard on telly. He wants to say something that matters - and hopefully be funny while he's at it.
Although, with his new gig he won't be able to be as provocative and potty-mouthed as he was on the no-holds-barred 7 Days.
"On 7 Days it was really anything for a laugh and sometimes you would say things and the message may not be 100 per cent something you agreed with, like a joke about Paula Bennett being fat. I don't think it's a great thing for a comedian to spend a lot of time talking about how fat a politician is, but when you're in that studio, with a live audience, you know you can get a laugh out of it.
"Whereas, in this role I'll have time to prepare, there will be less mayhem, so time to get your lines out, and it's a chance to do a little mental check: 'Is it funny? And what am I saying it for?'
"Like [US fake news series] The Daily Show, it's all funny, but at the end of the night Jon Stewart has done some pretty important stuff. That's my aim, and a challenge; to do funny stuff and make sure it's interesting and true."
Growing up in Hamilton, Mulligan was the "brainy kid at school", and was brought up on a steady diet of backyard cricket ("I spent most of my summer bowling to my older brother in the backyard, as he went on to score double centuries"), watching British comedies such as Black Adder and The Young Ones, and local series McPhail and Gadsby, and playing Scrabble (he's still a fan with his Twitter page wallpaper a customised Scrabble board).
He also admits to a strange fascination with talkback radio ("I used to listen to Radio Pacific, I love the format").
After school he studied law, and it was about this time he got a job as the joker on a local radio station - and his start in comedy - when he won a first-timer's stand-up competition.
"So I guess it was talk and news first and then I got up on stage at a comedy competition. So I did all that in parallel, but it wasn't until 7 Days that I really got to meld them into one job and do both."
These days, as well as expecting his second child, he is also a food writer, doing restaurant reviews for Metro magazine and writing his blog aucklandfoodblog.co .nz, and is proud of his "manbassador" role at charity Bellyful, which provides meals for families with newborn children and those in crisis ("food is the best thing you can donate").
But most importantly, given his new job, Mulligan remains a staunch news addict.
"It's about being connected. And my job for the past few years has been about the news, writing jokes about it and taking interesting angles on it. So in a way that's a personal thing, because I need to be connected to be employed. And as a comedian, topical references are your language, so missing a story is losing part of your language."
Last year, Mulligan met John Campbell in the street and suggested the idea that he could do some sort of funny slot each week on his show.
Mulligan says Campbell was characteristically encouraging - "He said, 'Yeah. Okay. Okay, Jesse. Yeah'," says Mulligan, doing his best Campbell impression - but of course nothing ever came of it.
Now he will be in direct competition with Campbell Live, though the two shows will be far different in format to old rival Close Up.
Then again, Mulligan doesn't see Campbell Live as the sole competition for Seven Sharp, because Twitter and those people who watch telly while tinkering away on their laptops and tablets are TV's main rivals these days.
"Because the day a big story breaks, as a comedy writer you can't actually compete with Twitter for one-liners," he concedes.
But Mulligan reckons it's time the 7pm current affairs time slot, which started with Holmes way back in 1989, was given an overhaul.
"Seven Sharp will really tear up the format and hopefully create a show that will have 10 years of life in it."
Who: Jesse Mulligan
What: Seven Sharp, starts February 4, 7pm, TV One
- TimeOut
