Winchell was born April Terri Winchell in New York City, New York on January 4, 1960.

In broadcasts of her KFI show, on her web diary and several other websites, Winchell revealed she and Kevin Spacey dated for a while after high school. She met art Director Mick Kuisel in 1988, and worked with him as a copywriter until his death in 2017. They were married in 1996. Since 2013, Winchell has been married to John Foley.

In 1992, Winchell and her then-husband Mick Kuisel formed Radio Savant Productions, a radio advertising production company. Since that time, Winchell has received many awards including Cannes, Clio, The $100,000 Mercury Award and The International Grand Andy (bestowed by The Association of Independent Commercial Producers) – it was the only time the Andy was given for radio. Winchell also provided the award-winning radio and television advertising for Big Bear Mountain Resorts for over 20 years.

Winchell worked on the 1996 video game Toonstruck in which she voiced a number of characters including Ms. Fit, Polly, Punisher Polly and Dr. Payne's Receptionist. Not only did she voiced the characters but she has also worked as casting and dialogue Director for the game. She also worked as a punch Writer for Recess: School's Out and wrote three episodes of the American sitcom Roseanne.

Besides her many contributions to radio advertising as a Director, Writer, and performer, Winchell also hosted a radio talk show program on KFI, a Los Angeles radio station. This weekend program aired for three years, and enjoyed the fastest growing audience in the history of the station. Subsequent to the end of this program in November 2002, she appeared semi-regularly on the Ask Mr. KABC program, on KABC, an AM station also in Los Angeles – until the show ended in February 2007.

On August 19, 2005, she announced on her website that she was diagnosed with stage 4 thyroid cancer. To promote solidarity during her radiation treatment, she issued her own "Glow in the Dark" wristbands, so one could "glow along" with April. She made a full recovery.

In 2005, Winchell signed a deal with U.S. pay-TV Service HBO to develop and host a show on Sirius Satellite Radio. However, on her official website on May 3, 2006, she announced that negotiations had stalled out between HBO and Sirius, leaving her program in limbo.

On March 16, 2007, she returned to semi-regular radio appearances on The Marc "Mr. K" Germain Show on KTLK-AM (the new show hosted by the former Mr. KABC) and appeared twice a month. (Her appearances on Germain's show are available at her website in addition to KTLK's website.) During March, Winchell was "banned for life" from KABC (AM) in Los Angeles at the behest of ABC radio host Bill O'Reilly, over a retelling of an occurrence she dubbed "Croissantgate" (KABC provided Bill O'Reilly with croissants that were not fresh enough for his taste, causing a commotion at the station).

Prior to 2009, Winchell maintained a personal Web site that, in addition to the music pieces, chronicled the actor's activities, which include her professional, personal, and romantic life. In October 2009, Winchell (under the pseudonym "Helen Killer") launched Regretsy, a blog website which satirized Etsy. Within four days, the site had received nearly 90 million hits. This huge viral success caught the attention of Random House, who subsequently won a bidding war to publish a book based around the Regretsy website. The book, which was published April 6, 2010, features humorous and bizarre crafts and artwork from several different artists, as well as essays about Winchell's personal life, childhood and own crafting failures. As of March 1, 2012, the Regretsy site had raised over $200,000 for charitable causes. The popularity of Regretsy's "Not Remotely Steampunk" section even inspired a viral "chap hop" music video. Winchell ceased updating Regretsy on February 1, 2013.

Winchell is also widely known as a supporter of various charity causes, including Project Angel Food, a Los Angeles-based Service providing meals for homebound people living with AIDS. Her website, Regretsy, generated charitable funds through selling of Regretsy merchandise. On, April 17, 2011, Winchell created April's Army, one of the largest selling teams on Etsy. The Army's members ran monthly campaigns, and all the profits gathered from their store went to a selected Regretsy member who has encountered hardships. On December 5, 2011, Regretsy began a Secret Santa program, collecting donations for presents for needy children. Regretsy raised so much money so quickly that PayPal froze the Regretsy account – as well as Winchell's unrelated personal account – for six months in order to "investigate." As this move effectively destroyed Christmas for 200 needy families, public outcry was massive, resulting in Regretsy becoming a worldwide trending topic on Twitter. After publicly apologizing, PayPal reinstated Winchell's accounts and donated $20,000 to the families she was raising money for.

Additionally, Winchell wrote and starred as "Sheila Sands" in her show at the Roxy Theatre in Los Angeles to sold out crowds. The show was produced by Lily Tomlin and Jane Wagner, who discovered her at Cafe Largo in Hollywood. Winchell reprised the character to open for Brad Garrett at the MGM Grand in Las Vegas in 2013.