Played by Betty White

Catherine Piper has appeared in more episodes than any other recurring character. She has been, at various times, a hostile witness, Alan Shore's assistant, the firm's sandwich lady, and, on several occasions, a client in need of legal assistance.

Mrs. Piper on The Practice
The character of Catherine Piper was introduced in the final season of The Practice when Alan Shore defended his boyhood friend Paul Stewart against murder charges.

Alan had known "Mrs. Piper" since he was a young boy growing up in Dedham, Massachusetts. At the age of nine, he had placed a burning bag of dog excrement on her porch as a prank. Not one to forget, Catherine greeted Alan in TP8x13 [Going Home] with an excrement-tainted handshake. Catherine was a hostile witness with incriminating information that she used to extort Paul's mother. Nevertheless, she ended up testifying as a prosecution witness during the trial. To counter her testimony, Alan portrayed Catherine as an unstable and vindictive witness.

Catherine at Crane, Poole & Schmidt
The Catherine Piper of Boston Legal is not quite the same conniving schemer depicted in The Practice. However, her sharp tongue and forthright manner remain unchanged.

She first appeared in episode 1x12 [From Whence We Came] when she applied for the job of Alan's assistant, saying "Most people aren’t able to see that beneath your slick and sensitive exterior, deep down you really are douche bag. I get that, Alan. You’d have no misunderstanding with me."

This line of reasoning must have resonated with Alan because she was next seen serving cookies at the morning staff meeting in 1x13 [It Girls And Beyond].

Catherine and Bernard Ferrion
Catherine met murder suspect Bernard Ferrion in her first visit to Alan's office and immediately dubbed him "an adorable little man". She encountered him again in 1x15 [Tortured Souls], when she tried to convert the Jewish Ferrion to Christianity. The two seemed to click despite Alan's best attempts to dissuade Catherine from befriending the man who had already killed two women in his life: "Catherine, Bernard Ferrion is evil. He will likely murder again. And you? If there was ever a person who deserved a whack on the head..."

By episode 2x01 [The Black Widow], Catherine and Bernard were clearly an item, and in 2x02 [Schadenfreude], the two were dining together in Bernard's kitchen, with Catherine apparently having taken up residence. But Catherine soon began to fear for her life and eventually killed Bernard using his own modus operandi - two whacks in the head with a skillet.

Catherine hid Bernard's body in a freezer and failed to tell anybody about his demise for a week until he was noticed missing. After admitting what had happened to police, she was arrested in 2x03 [Finding Nimmo] and put on trial for murder in 2x04 [A Whiff And A Prayer]. She was represented by Alan, who argued that she had acted out of fear for her own life. The jury found her to be not guilty.

More Legal Troubles
In 2x05 [Men To Boys], Shirley Schmidt fired her from her position at Crane, Poole & Schmidt, saying, "We simply cannot have administrative staff killing clients".

Catherine was not seen again until 2x13 [Too Much Information], when she went on a crime spree, robbing two convenience stores. Alan managed to get the charges against her dropped both times, and he eventually realized that her acts were a cry for attention. To help her feel more involved, he got her a position as the sandwich lady at Crane, Poole & Schmidt.

Catherine has only been seen in one other episode as the sandwich lady - in 2x14 [Breast In Show], she pushed first-year associate Garrett Wells out of his office and into the hallway, so she could have an office of her own.

In 2x20 [Chitty Chitty Bang Bang], Catherine got into more trouble when she was accused of kidnapping her friend Adele Freeman from an assisted-living facility. It's not clear whether she was actually arrested, but Alan somehow helped her escape the charges yet again.

In 3x04 [Fine Young Cannibal], Catherine made a credited but non-speaking appearance as the sidekick of Alan's imitation of "Chief Jay Strongbow" in his wrestling match with Denny Crane.

Betty White
The legendary 84-year-old Betty White has won six Emmys in her career and is a member of the Television Hall of Fame. Her first Emmy win came over 50 years ago for the comedy Life With Elizabeth, a show she also co-produced - quite unusual for a young woman in that era. After that experience, she made a career of featuring in variety and game shows before returning to sitcom work in The Mary Tyler Moore Show (1973-77), for which she won two more Emmys. White appeared in two episodes of St. Elsewhere (1985) with fellow Boston Legal guest star Ed Begley and played something of a precursor to Catherine Piper in David E. Kelley's 1999 film Lake Placid. That same year, she also appeared in an episode of Ally McBeal.

Betty White at the Internet Movie Database
Betty White at Wikipedia

Episode appearances:
1x12 [From Whence We Came]
1x13 [It Girls And Beyond]
1x14 ['Til We Meat Again]
1x15 [Tortured Souls]
1x16 [Let Sales Ring]
2x01 [The Black Window]
2x02 [Schadenfreude]
2x03 [Finding Nimmo]
2x04 [A Whiff And A Prayer]
2x05 [Men To Boys]
2x13 [Too Much Information]
2x14 [Breast In Show]
2x20 [Chitty Chitty Bang Bang]
3x04 [Fine Young Cannibal]