Kate Bolduan's ancestors arrived in America in 1912. The came from a small town called Chênée in Belgium. Leon Emile Rousselle (Bolduan's great-great-grandfather) took the SS Kroonland two month before his pregnant wife Louise Labhaye Rousselle and his two year old daughter aboard the SS Lapland (which rescued some survivors of the Titanic catastrophe). The Rousselle's came from a long line of glass manufacturers. In 2014 Bolduan travelled to Liège in Belgium to find out about her family history.

A native of Goshen in Indiana, she is the third of four daughters born to Dr. Jeffrey Bolduan, and to Nadine Bolduan, a nurse. She was educated at Goshen High School, a public high school in her home city, followed by George Washington University, from which she graduated Phi Beta Kappa in 2005, with a bachelor's degree in journalism. During her time at the university, she walked on to the women's volleyball team and acted with the student theatre organization.

Bolduan began her tenure at CNN as a national correspondent for CNN Newsource. She provided breaking news coverage and feature reports for a large number of CNN Newsource affiliates. During her time there, she most notably covered the 2008 United States presidential election and traveled throughout the United States covering other news making headlines including the Minneapolis Bridge collapse, the O.J. Simpson armed robbery case, and the retiring NASA Space Shuttle fleet.

In May 2010, Bolduan married Michael Gershenson, who works for The Carlyle Group. Bolduan has converted to Judaism. They moved from the Washington D.C. area to New York in early 2013 after Bolduan accepted the anchor position at CNN's morning lineup.

New Day is a weekday morning television show on CNN. It premiered on June 17, 2013 and airs from 6:00 a.m. to 9:00 a.m. ET, originating from CNN's Time Warner Center studios in New York City. New Day replaced Starting Point, formerly anchored by Soledad O'Brien, which had aired since January 2, 2012.

Bolduan joined CNN's new morning show, At This Hour, which premiered on January 26, 2015, alongside John Berman. At This Hour covers various news stories of the day with co-hosts Kate Bolduan and John Berman. At This Hour airs weekdays from 11 a.m. to noon ET, and is broadcast live from CNN's New York Studios in Manhattan. On February 6, 2017, Berman moved to 9 a.m. to co-host CNN Newsroom and Bolduan took over as the sole host of At This Hour.

Bolduan was named anchor of her own CNN International program covering the 2016 U.S. Presidential race for a global audience. Following the election, the program was renamed and pivoted to focusing on U.S. news and affairs. The show airs weekdays at 2:30 p.m. ET, live from CNN's New York Studios in Manhattan.

The couple’s daughter Cecelia Eve Gershenson was born in September, 2014; their second daughter Delphine Esther was born December 23, 2017.