Louise was born and raised in Northampton. When she was seven years old, her mother died of metastatic breast cancer. Louise posted a video in October 2015, titled "My Pink Hair Story", in which she goes into detail about her mother's death. Her father later remarried and Louise suffered mental and physical abuse from her step-mother. While at school at Northampton High School, Louise experienced bullying. Pentland graduated with a Bachelor of Science with Honours in Psychology and Biology from Liverpool John Moores University in 2006.
Louise was working in a number of office roles when she began writing a craft and interior DIY blog named "Sprinkle of Glitter". As of March 2015 the lifestyle, fashion and beauty blog had over 159,000 followers.
She began her YouTube channel, also named "Sprinkle of Glitter", in January 2010. At first the channel covered beauty, fashion and lifestyle, as well as her pregnancy; it has since expanded to include motivational and advice videos. In August 2012, she began a second channel named "Sprinkle of Chatter", where she uploads lifestyle vlogs. Louise has broadcast many collaborations on her channel with other YouTubers, including: Zoe Sugg, Joe Sugg, Alfie Deyes, Louis Cole, Tanya Burr, Tyler Oakley, Troye Sivan, Grace Helbig, Phil Lester, Dan Howell, Caspar Lee, Jim Chapman and others.
As of August 2016 Louise's main YouTube channel has over 2.5 million subscribers and over 150 million video views; her second channel "Sprinkle of Chatter" has over 1 million subscribers and over 85 million views. Pentland is influential in social media, with over 1 million followers on Twitter and Instagram.
Louise has identified as a feminist and interviewed Labour Party leader Ed Miliband during the 2015 United Kingdom general election.
In 2014 she began Q&A sessions with her viewers at YouTube conventions named Glitter Time. On November 2, 2014 she performed a pilot of her LouiseLIVE stage show in Northampton, her home town, and went on to take it on tour around the UK.
On September 1, 2016 she announced in the blog post "Why I'm 'Quitting' My Youtube Channel" and the video "Finishing with Sprinkle of Glitter" that she will be quitting her YouTube channel as it is now, and change to something more 'adult', as she feels she has grown up a lot since the start of her channel, and it's time for something new and something she feels is more 'Louise Pentland', instead of 'SprinkleofGlitter'.
"Life with a Sprinkle of Glitter" was published in July 2015 by Simon & Schuster. The following month she published "Sprinkle of Glitter 2016 Diary: Have the Best Year of Your Life!" through Faber and Faber.
Bonnier Zaffre acquired rights to two novels in 2016. The first, "Wilde Like Me", was published in June 2017.
Louise married Matt Watson, a teacher, on September 4, 2010; their daughter Darcy Jane Watson was born in 2011. Louise and Matt separated in mid-2014, but both stated in 2015 that they remained on good terms.
She stated in a vlog on April 14, 2016 that she was in a relationship with an unnamed man; two months later on June 11, 2016, she made another vlog revealing that they had split.
In a main channel video on October 14, 2016, she announced that she was in a new relationship with a 40-year-old man named Liam. On June 14, 2017, she announced that they were expecting their first child together, and on August 2, 2017, she announced that the baby was a girl. On December 18, 2017, she announced the baby's name was going to be Pearl Jane Pentland. Louise gave birth to Pearl naturally at home at 42 weeks pregnant in the morning of January 14, 2018. She announced her second daughter's birth the next day via her social media, stating that she had wanted the day before to herself to be with Pearl.