The main cast of The Big C centers on a suburban teacher dealing with a terminal cancer diagnosis and the people closest to her.

Main cast

  • Laura Linney as Cathy Jamison, a Minneapolis–Saint Paul high school teacher diagnosed with stage IV melanoma who tries to live more boldly after her diagnosis.
  • Oliver Platt as Paul Jamison, Cathy’s well-meaning but often immature husband.
  • Gabriel Basso as Adam Jamison, Cathy and Paul’s teenage son.
  • John Benjamin Hickey as Sean Tolkey, Cathy’s eccentric and homeless-activist brother.
  • Gabourey Sidibe as Andrea Jackson, a student Cathy mentors who becomes an important part of her life.
  • Phyllis Somerville as Marlene, Cathy’s elderly neighbor who learns about her illness and becomes a confidante.

Notable recurring actors

  • Cynthia Nixon as Rebecca, Cathy’s long-time friend, appearing mainly in the earlier seasons.
  • Reid Scott as Dr. Todd Mauer, Cathy’s oncologist.
  • Hugh Dancy as Lee Fallon, a fellow cancer patient who befriends Cathy.
  • Idris Elba as Lenny, a charismatic painter Cathy becomes involved with.

Quick HTML table of key cast

Actor Character Role type
Laura Linney Cathy Jamison Lead
Oliver Platt Paul Jamison Main
Gabriel Basso Adam Jamison Main
John Benjamin Hickey Sean Tolkey Main
Gabourey Sidibe Andrea Jackson Main
Phyllis Somerville Marlene Main / recurring
Cynthia Nixon Rebecca Recurring
Reid Scott Dr. Todd Mauer Recurring
Hugh Dancy Lee Fallon Recurring
Idris Elba Lenny Recurring
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