This page contains spoilers for episodes 1x01 - 1x14 of "Brothers & Sisters"!
The second youngest of the original five-sibling Walker clan, Kevin is a 30-something attorney - and a remarkably good one, at that. Outside of the office, however, is where he gets himself into trouble. Kevin has a terrible case of foot-in-mouth, especially when it comes to his romantic entaglements.
When we first meet Kevin, he is talking his big sister Kitty through a cooking crisis, then teasing her about her sordid date with her gorgeous boyfriend. We don't learn much more about Kevin until Scotty Wandell walks into his office to discuss insurance fraud - and immediately calls Kevin on being gay. Scotty is cute, flirty and refreshingly blunt - he sees Kevin for the insecure and slightly lonely man that he is.
After a little bit of impromptu scheming from his big sister, Sarah, Kevin finds himself with more Scotty in his life than he bargained for. He tries to excuse Scotty from his life and fails miserably, unable to come up with any really good reason he should. As the two begin a tentative relationship, it quickly becomes clear that Kevin has a lot of lingering issues with his sexuality and relationships in general.
Though they shared a mutual attraction and admiration for one another, Kevin and Scotty often had very differing opinions on... everything. Easily flustered, Kevin often said things that unintentionally offended or insulted Scotty, who eventually realized that no matter how much he loved Kevin, and no matter how good the good was (and it was!), there was no future in their cards until Kevin learned to love and be comfortable with himself.
Kevin was hit hard by losing Scotty, and threw himself into bettering his physical health by siging up for a "boot camp" exerise class. There he met Chad Berry, a popular soap opera star. The two hit it off, with Kevin immediately smitten and convinced Chad was gay, until Sarah told him about the girlfriend. Baffled by that knowledge, and the continual flirting with him that Chad did, Kevin finally came right out and asked.
The answer was not what he had been expecting, or hoping for. Though he had a girlfriend, Chad was also attracted to men - but fear for what that might do to his career kept him firmly in the closet, only giving in when he was certain no one would find out. As Chad and Kevin became the one-night-stand that lasted much longer than that, Kevin became increasingly unhappy with being a secret - especially since Chad continued to see his completely oblivious girlfriend.
In an effort to make Chad jealous, Kevin allowed his girlfriend to set him up with a great guy she knew that Kevin would just love. To the surprise of both, the great guy turned out to be Scotty. The two shared a doomed-from-the-start night together, culminating the next morning in Scotty discovering just how well Kevin and Chad knew each other - and Chad laying the guilt card heavy onto Kevin.