How did it happen so fast? How did it come and go, in those five short weeks last season, after he'd waited two years for that potentially life-changing moment?
Yes, lurking in the shadows of the Redskins' recent drama, buried beneath the biggest headlines of the NFL regular season, there is a story flying under the radar about the patience and perseverance of one of the league's more likable players.
Regardless, consider the fortitude endured by Cousins since he became a pro:
» In 2013, he handled the drama facing Griffin and then-coach Mike Shanahan with perfect grace, even though his name was often dragged into the mess as Shanahan's perceived favorite.
» And then, in 2014, when he got that unlikely shot, it started so well before sinking so fast.
"I was feeling like I hadn't done the job," Cousins said. "Anybody who has a job to do and doesn't feel like they got it done, you have that feeling where, 'Shoot, I wish I could do it over again.' But I can't. It was tough.
"At the same time, tough times don't last. Tough people do. I just had to keep going, and if I kept doing that, I'd have another chance. And here we are."
Indeed, here we are. Cousins now has new life with a perfect chance to prove his worth as a starting quarterback in the NFL, and he has the support of those around him.
So often in recent weeks, many have suggested the players in the locker room like Cousins more than they like Griffin, which is creating a sense that a popularity contest exists within the organization. That discussion, much like so many other conversations about Cousins, is missing a much bigger point.
This isn't about whether players like Cousins more. It is merely about the fact that players really, really, really like Cousins.
"It's how he lives, how he acts. He's just a good guy who does the right things on and off the field. He's just a good, all-around dude."
Of course, it now comes down to how Cousins performs on Sundays, starting with the one on the immediate horizon, against one of the best projected defensive fronts in the NFL. And really, it's difficult to gauge exactly how he'll do.
As coach Jay Gruden has pointed out, Cousins has had his share of battles with consistency, the most notable of which occurred during his five-week stretch last season as the starter. Cousins posted a passer rating of 103.4 in his first game in the role, after posting a passer rating of 109.4 while filling in for an injured Griffin in Week 2. But then came a passer rating of 53.0 in Week 4. Then 102.0. Then 78.2. Then 64.3.
In other words, he was all over the map, perhaps in part due to the pressure he felt to perform, or his inexperience as a starter. Regardless, it wasn't good enough.
"Obviously, we're disappointed that he had an opportunity to take [the job] and he had some interception issues and all that stuff," Gruden said. "But we feel good about him moving forward. You know, when you get in the second year in a system, there's a comfort level. Certain quarterbacks take a giant leap, certain quarterbacks don't.
"I feel like Kirk has taken a giant leap so far."
For Cousins' part, the quarterback believes he's come to "recognize defenses better, recognize coverages, blitzes, pressures; my movement in the pocket needs to be better."
These are all things he realized he needed to improve upon once he lost the starting gig last year. Cousins said Wednesday it took him some time to snap out of the funk he felt after McCoy replaced him in Week 7. Soon, though, he began to focus on what it would take to get back to where he'd been.
And now, as a result, he's feeling very calm and at peace with the current opportunity in front of him.
"It's just so important to take deep breaths and say, 'Alright, this is big. It's a great opportunity, but I don't want to make it bigger than it is,' " Cousins said. "I'm going to try to be in that sweet spot where I'm relaxed but focused."
No doubt, during this path to this point, Cousins has wondered what it was going to take to get here. That was the case when he was drafted three rounds after Griffin in 2012. And it was the case again when he was benched for McCoy in 2014.
Now he can only wonder if it was all meant to be, if it all unfolded as it should, so he had the best chance to succeed when it was finally his job and his team. He can't look back and question why or how it happened.
But he can look forward, knowing the sleepless nights are behind him for the moment -- and will remain behind him if he can take advantage of this latest reward for his effort and patience along the way.
"I do believe, from the day I was drafted, that God brought me here," Cousins said. "He's got a plan for me. The plan may not be to win Super Bowls and throw a bunch of touchdown passes and win a bunch of games. I hope it is part of the plan, but I just trusted that he had a plan for me and that he was going to work everything out."