Today is the first day of the rest of Michael Strahan’s professional life — as newly minted co-host on “Good Morning America” — unless it’s not. Anything could happen. Anything usually does in TV. (Anything already has.)

But Tuesday is indisputably among the biggest days in “GMA” history. This bet-the-farm move has already destabilized another ABC franchise, wrecked a TV “friendship,” launched a public feud and dragged in top Disney officials (indeed, the top one — Bob Iger) to limit the damage. Kelly Ripa — back on “Live!” today for a new season — continues her search for a replacement. From a practical standpoint, the fallout from Strahan’s sudden departure in May continues, and therefore, this is a big day for two major ABC franchises.

As such, the timing for both “GMA” and Strahan is complicated. NBC’s “Today” is still riding the wave caught during the Olympics and for the moment is TV’s most-watched morning show. Strahan is here to erase that advantage.

Will he? Won’t he? Can he? Those are the questions. Here’s what viewers saw in the way of preliminary answers Tuesday morning:

The same old Strahan, for the most part, with his smooth demeanor and effortless ability to laugh at something that’s not particularly funny but still requires an outsized reaction just the same. Like instant coffee, morning TV requires instant camaraderie and instant chemistry. Strahan’s already had a few years here to work out the kinks. He knows his way around this show already. That’s the advantage going in, and his advantage, too.

“It’s great to have you full time,” co-host Robin Roberts said. “It does feel like the first day of school around here.”

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Quipped the same old Michael: “Only thing I’m missing is my Spider-Man lunchbox.”

The show proceeded from there — busily. There was hard news (George Stephanopoulos is expected to do the heavier lifting there) and lots of light stuff — the fluff or detritus that fills morning TV, this show in particular. New “View” co-host Sara Haines showed up for a segment. There was another one on “summer vacation photo hacks” — family photos arrayed for the perfect occasion.

Lara Spencer was on the phone, too. She underwent hip-replacement surgery last month and is still recovering. Spencer was rumored to be leaving the show when the Strahan appointment was announced in May.

“I’m feeling great,” she said. “Walk a mile a day . . . ”

“You take care of you,” Roberts said. No word on when, or if, Spencer will actually be back.

More busy-ness: Usher, a Strahan pal, turned up, and later Meg Ryan, promoting her new movie (“Ithaca”), and after that, the boy who played a “Mini Me” version of Strahan in the ubiquitous promos that led up to Tuesday’s launch.

Strahan handled the conveyor belt expertly — he always does — but something, or someone, was missing. On this, the first day — much like all the past days when Strahan was an occasional “GMA” stand-in — it’s still not entirely clear that this show plays to his strengths. At “Live!” he was the star attraction. At “GMA,” he’s second, or arguably even third billing behind Roberts and Stephanopoulos.

At “Live!” he tethered Kelly to the desk, or chair, and she — in some sense — returned the favor. They complemented each other and — in that strange way that chemistry contributes to successful teams (but good luck defining exactly how it does that) — they made each other better.

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At “GMA,” there’s no one to improve, or complete. Roberts is already a star, and the star. She’s a person of substance who holds down an insubstantial show. She doesn’t need someone to make her “better,” or smarter, or funnier or more competent. She’s already all that and more. Strahan doesn’t particularly add anything to her, or vice versa. It’s not that chemistry is lacking, per se. It’s just that chemistry isn’t particularly necessary.

Strahan is also someone who likes attention, and likes to be the center of attention. He’ll get some of that here, just much less of it. The spotlight — and camera — doesn’t linger on anyone for long at “GMA,” but if it does linger, Roberts is the recipient. She’s the franchise player; he’s the new guy. He’ll have to get used to the new pecking order — and viewers will, too.

Strahan had the perfect job at “Live! With Kelly and Michael.” He now has the imperfect one at “GMA.” That may not be progress, but it is showbiz.