Ludvig Strigeus, the creator of ScummVM, also made µTorrent and was an early employee of Spotify after Daniel Ek, one of Spotify's founders and CEO, bought µTorrent as an acqui-hire. He got 5% of the shares before their IPO and still works there.
So that's three impactful programs from the same person.
Ludvig is one of the best systems-level computer programmers of this era. His focus is on optimization in every way has been the secret to success for these projects; something that is sadly missing in most software these days. µTorrent came about when other torrent software was heavy so it took over the market. The Spotify Desktop client came when instant streaming music online was a lot more difficult than it is now, and the case for ScummVM is obvious. He was one of those assembly and C win32 programmers who wrote code as close to the OS as possible, even when .NET and Java and even MFC had major marketing pushes.
I was on a puzzle team with him and he was our secret weapon, programming brute force "scripts" to find the solution before anyone could solve it logically, winning us the competition handily. And I also remember (wrongly) discouraging him from making µTorrent because I felt it was already a saturated field. Luckily he did not pay attention to my suggestion.
µTorrent was available as a native macOS app for a long time. They dropped support in macOS Catalina. Apparently going 64-bit was too hard. Now they just offer some shitty web client.
The Spotify podcast[1] details his hiring and the impact he had on the initial desktop application. Seems like it was a really impressively engineered piece of software. They did a lot of customization and hacking on protocols/encodings to make playing a song instant
So that's three impactful programs from the same person.