An idiosyncratic FBI agent, Cooper arrives in Twin Peaks in 1989 to investigate the brutal murder of popular high school student Laura Palmer, and begins to uncover several bizarre mysteries around the town, including some supernatural ones.
[2] MacLachlan has stated that he views Cooper as an older version of his character in Blue Velvet (1986), a previous David Lynch collaboration.
[4] Cooper displays an array of quirky mannerisms such as giving a "thumbs up" when satisfied, sage-like sayings, and distinctive sense of humor along with his love for a good cherry pie[5] and a "damn fine cup of coffee"[6] which he takes black.
At some point, Cooper would be placed under the authority of FBI Chief Gordon Cole (David Lynch), which sometimes meant being handed the mysterious 'Blue Rose' cases.
Initially, the prime suspect is Laura's boyfriend Bobby Briggs (Dana Ashbrook), but Cooper quickly determines he is innocent.
When BOB forces Leland to commit suicide, Cooper helps him transition into the afterlife by reciting a Buddhist prayer for the dead.
In the final episode of Twin Peaks, Cooper enters the Black Lodge to rescue his new girlfriend, Annie Blackburn (Heather Graham), from Earle.
Twenty-five years after the events of the original series, Cooper remains trapped in the Black Lodge, while his doppelgänger continues to assume his identity in the natural realm.
With help from entities both inside and outside of the Black Lodge, as well as Diane (Laura Dern) in her Naido form, Cooper is finally able to leave.
Upon his return to the natural realm, he is left in a near-catatonic state, unable to perform basic tasks without assistance and rarely speaking besides repeating words he hears.
Cooper also becomes the target of an assassination plot organized by corrupt businessman Duncan Todd (Patrick Fischler) on orders from his doppelgänger.
Cooper eventually starts to come out of his near-catatonic state after hearing Gordon Cole's name spoken while watching the film Sunset Boulevard.
With BOB and the doppelgänger defeated, he then visits Phillip Jeffries (Nathan Frizzell), who sends him to the night of Laura Palmer's death.
As Cooper asks what year he is in, Carrie hears Sarah shouting Laura's name, causing her to scream and the lights in the house to go out.
The feature film Twin Peaks: Fire Walk with Me subtly expands on the events of Cooper's fate in the series finale, while at the same time functioning as a prequel that details the last week of Laura Palmer's life.
A year prior to Laura's murder, Cooper witnesses missing FBI Agent Phillip Jeffries (David Bowie) appear in Cole's office before mysteriously disappearing again.
When MacLachlan guest hosted Saturday Night Live in 1990 at the height of Twin Peaks' popularity, the episode contained many references to the series throughout.
Cooper is portrayed in the sketch as being extremely attentive to detail in his messages to Diane, including informing her of how many hairs he found in his shower the night before.
Sheriff Harry S. Truman (Kevin Nealon) then visits Cooper, telling him that Leo Johnson (Chris Farley) has confessed to the murder of Laura Palmer and that he can go home.
Cooper protests that the case can not be over so soon and insists in vain that he and Truman perform several pointless tasks in order to aid him in the already solved investigation, including going to a graveyard at midnight disguised as altar boys.
Caroline's death and his failure to protect her continues to haunt Cooper on his arrival to Twin Peaks, referring to a "broken heart" when discussing women with Truman and his deputies.
Following her rescue, there remains a close and affectionate friendship with the two, most notably when Audrey arrives to his hotel room for comfort following her father's arrest and her sad farewell when she believes Cooper is leaving Twin Peaks for good.