For the last three years, NBC's smash hit series This Is Us has been a very popular and well-received series, both from a critic and audience member perspective. The series has chronicled the complicated family history and ever-expanding family tree of the central Pearson family, following them through the past and present across multiple generations and always having an eye toward future generations, too.

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While the series may revolve primarily around the nuclear family of Jack, Rebecca, Randall, Kate, and Kevin Pearson, various other characters - both Pearson and non-Pearson - have played key roles in the series so far. Here, we're taking a look at how the series' characters compare to one another, and offering a definitive ranking of the top 10.

Kevin Pearson

Honestly, we considered leaving Kevin off this list. From day one, Kevin has been the most frustrating of the Pearson children, incredibly self-centered and arrogant. However, over time, he's revealed a softer side to his character, most notably through his relationship with twin sister Kate and his personal struggles.

Kevin might not be the best member of the Pearson family, but he's got the potential to work his way higher up this list, if his journey of self-discovery and maturity pans out the way it should in future seasons.

Rebecca Pearson

Another member of the Pearson family who's been polarizing and frustrating on more than one occasion is matriarch Rebecca Pearson, who had the tremendous difficulty of raising three teenagers all on her own after Jack's tragic death. There's no denying that she did a great job, given how her kids turned out as adults.

She also made her fair share of mistakes both in the past and present, especially concerning her issues with Kate's weight and career, her tendency to ignore Kevin, and her repeated omission of the truth from Randall. She's learning from her mistakes, however, and that's what really matters.

Kate Pearson

Teenage Kate Pearson in This Is Us

Kate Pearson has come a long way from the little girl known as Katie Girl in the flashbacks to the Pearsons' childhood years. She's not as bouncy and innocent as she once was, nor is she the moody, struggling teenager she was during her difficult adolescent years.

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The Kate we know and love as an adult is a woman who has finally accepted herself for who she is, flaws and all. Though we wish her storylines would explore issues unrelated to her ongoing weight struggle more often than they currently do, we can't deny that we're excited to explore this new chapter of motherhood with Kate, and to see what happens with her ventures into music, too.

Toby Damon

This Is Us Toby

Truth be told, when Toby was first introduced in the series, he definitely came on more than a little bit too strong in some fans' opinions. With his pushy personality and grand gestures, some felt that he was overstepping boundaries left and right. Over time, though, it became clear that Toby was exactly what the Pearson family needed, and a key player within the series, to boot.

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Not only is Toby Kate's perfect other half, he's been a great quasi-brother to both Kevin and Randall, offered key moments of reflection for Rebecca, and formed a hilarious friendship trio with fellow "outsiders" Miguel and Beth.

Annie Pearson

Faithe Herman as Annie Pearson in This Is Us

Annie Pearson might be the youngest character on this list, but there's no denying the impact she has had on the series, in some of its most emotionally resonant moments. Not only does Annie add a necessary dose of cuteness and levity to the series, she also allows some of the adults to let down their guards.

Particular highlights of her character's journey include her many scenes with her late grandfather, William, which allowed a look into the insight possessed by this pint-sized cutie, as well as the older and initially much more jaded man.

Dr. Nathan Katowski

Dr Nathan Katowski talking to someone in This Is Us

Gerald McRaney's beloved OBGYN Dr. Nathan Katowski has only appeared in a handful of episodes so far. Even in those brief appearances, Dr. K has more than proven his importance in the overall legacy of the Pearson family, and This Is Us overall.

From the moment he was introduced in the pilot, to the imparting of wisdom regarding making lemonade out of the worst lemons imaginable, to his heartbreaking backstory, Dr. K has been one of the series' most reliable sources of wisdom and emotion in equal measure. We wish he was around more often, but we're more than grateful for every bit of lemonade his character provides.

Beth Pearson

Beth Pearson looking serious in This Is Us

From day one, Susan Kelechi Wastson's Beth Pearson has been Randall's true partner in crime and an amazing mother and role model to her daughters. It wasn't until the series' third season that the many layers of her character truly began to be explored, revealing a vulnerable and brave woman beneath the superhero veneer.

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Beth lost her father at a young age, much like the Pearson clan did, and as a result of that, she was forced to put her lifelong dream of dancing on hold in favor of supporting herself and her family. Still, with the resurgence of a truly fiery and awe-inspiring passion, Beth has decided she won't defer her dreams any longer, setting the course for truly exciting territory in the season to come.

William Hill

William Hill in This Is Us

Oh, William. Two full seasons have passed since This Is Us lost this soulful, unlikely patriarch, and in truth, the series has never really been the same since the advent of his absence. Beautifully portrayed in the present by Ron Cephas Jones, and in the past by Jermel Nakia, William is one of the series' most damaged characters, but also one of its kindest, most loving, and wisest.

After struggling with addiction for much of his life, and giving up Randall soon after his birth, William found his way late in life, finding love in the form of his boyfriend Jesse, and a heartwarming and heartbreaking bond with Randall when he only had one year to live. William's tenure on the series may have been short, but his impact will last forever.

Jack Pearson

This Is Us Jack Pearson

As the tragically departed patriarch of the Pearson family, Jack Pearson has long been on of the series' most mysterious characters, but also without question one of its most beloved. From day one, Jack has been redefining what it means to be a man, a father, and a husband, and setting lofty goals for men everywhere in the process.

Jack is not without his many demons. Battling alcoholism for much of his life, as well as repressing his many painful memories, Milo Ventimiglia's Jack Pearson might not be the perfect man everyone makes him out to be. He's a very real one, though.

Randall Pearson

Randall discourages a patient against pursuing love on This Is Us

For three seasons now, Randall has been the true beating heart of both the Pearson family, and the show as a whole. Whether we're focusing on his time as a child, as a teenager, or as an adult, Randall routinely overcomes the most difficult of situations with grace, integrity, and a whole lot of heart.

Randall started his life abandoned on the front step of a firehouse. How far he has come since then - as a man, as a husband, as a father - is merely a testament to the strength of his character, and the true tenacity of his spirit. In short, Randall Pearson is This Is Us.

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