Season Two

At the start the of the season, Tommy and Julia are struggling due to the death of their son. Julia decides they need some time apart and goes to stay with her parents. During her time away Tommy begins an affair with Lena (Emily Rose) - his new secretary and good friend of Rebecca.

Nora enters into a new romance with Isaac Marshall (Danny Glover) after meeting him when Kitty brings him in to assist with Robert's campaign.

Sarah now has to deal with being a single parent, and begins a relationship with Graham (Steven Weber), who comes to work at Ojai. After a business deal, which Sarah is reluctant to agree with in the first place, goes wrong she decides to take the heat and to leave the family business.

After Kevin breaks up with Jason he is reunited with Scotty, but they have their share of problems as their relationship becomes more serious. At the same time, Kevin is trying to get his uncle Saul to admit to who he really is, causing a rift in their relationship. They finally get married in the season finale.

Kitty and Robert plan their wedding as well as deal with Robert's campaign. Kitty later discovers she is pregnant, but there are complications with the pregnancy and the couple has to deal with a terrible loss.

Rebecca has spent the summer with Nora helping her deal with Justin being away at war. After he returns, due to an injury, Rebecca stays to help him recover. Soon after arriving home, Justin begins to lose control and becomes addicted to his pain medication. This, coupled with his relationship with Lena, causes him to have a falling out with Rebecca, who decides to move back in with her mother.

Rebecca then meets David, an old friend of Holly's, which leads to her discovery that she is not in fact a Walker and that David is her real father. After trying to hide this from the Walkers, in fear of being rejected, she finally comes cleans and each of them tell her that she will always be part of the family. Sarah, then becomes suspious as to why Rebecca's intials along with her other siblings opened the secret accounts in Season 1 and with Kevin's help they discover their father had another affair and that there is in fact another Walker out there.

Toward the end of the season, Justin must try to hide and deny his growing feelings for Rebecca, and after he admits how he feels, she reveals that they are not related and believes that everything that has happened was meant to bring them together. The season ends with Justin and Rebecca sharing their first kiss.

Season two of Brothers and Sisters consisted of only 16 episodes due to the 2007–2008 Writers Guild of America strike. Ten of the episodes were shown beforehand, ending with "The Feast of Epiphany"; a further six episodes were produced to finish off the season. The first half of the season dealt with many issues and plot points left unresolved from the first season. After the strike, they decided to wrap up these stories so they could start fresh for the following year.

In the UK the show changed to Channel 4's sister Channel E4 beginning March 30 and ending in July. The series was then repeated on Channel 4 in October of the same year around 4:30 pm on Saturdays, but after a couple of weeks moved it to Sunday nights in an unspecified time slot after midnight.

The second season ranked #38, one place down from the previous year and averaged at around 11.5million viewers.