The 39-year-old has been an actor for most of his life, with his career first getting jump-started around the year 2000.
In 2005, he got his breakthrough role as Jim Halpert on The Office, and audiences have continued to fall in love with Krasinski ever since.
Scroll down to see how much the star has changed over the years, and let us know in the comments which of his roles is your favorite!
The Office, Season 1
In the first season of The Office, Krasinski has a baby-faced look, complete with a rounded, smooth features. The fresh actor also donned a shaggy hairstyle that gave his character a very "I didn't try very hard, I'm just naturally this adorable" quality.
The Office, Season 3
When Season 3 of The Office rolled around, Krasinski had mostly kept his hair the same, but he was now styling it a little messier. He had also taken full advantage of his 5 o'clock shadow, something that became a bit of a prophesy for many years later.
The Office, Season 5
Again, not a whole lot changed over the next couple of seasons, but by Season 5 of The Office, Krasinski had noticeably thinned out some. The one other difference was that he had trimmed his hair just a bit, but was still rocking the messy look that he made so popular.
The Office, Season 7
Krasinski really showed show major aesthetic changes come Season 7 of The Office, with the actor appearing to have a much more defined jawline and slimmer appearance. He also traded in the messy hair style for a combed swoop, that also became a trend-setting look.
The Office, Season 9
The final season of The Office saw Krasinski fully embracing his Hollywood Heartthrob status. His hair was much more dapper, and his beloved business-casual style had made him a household name.
After the Office ended, Krasinski did a few small projects, and then came back to shock everyone by sporting a full beard in the Michael bay non-fiction action film 13 Hours: The Secret Soldiers of Benghazi.
The role also saw Krasinski bulk up to play former U.S. Navy SEAL Jack Silva, a look that suited him well.
A Quiet Place
Earlier this year, Krasinski co-wrote, directed, and starred in the hit horror film A Quiet Place.
That film featured the actor's beard looking more bushy than ever, and proved that even in a post-apocalyptic wasteland under siege by bloodthirsty creatures Krasinski is still a handsome fella.
Tom Clancy's Jack Ryan0comments
Krasinski's most recent role is the title character in Tom Clancy's Jack Ryan. The star has reverted back to his roots for the part, trading in the bearded look for a clean-cut appearance circa-The Office Season 9.
It just goes to prove that no matter where he goes, or what he does, Krasinski will always be Jim Halpert in our hearts.