Lady Borwick won the seat with 18,199 votes. Labour received 10,838.
Speaking after the declaration, the new MP said that she had "grown up on the streets of Kensington" and intends to "represent all of those who live in the borough".
Labour's Rod Adouharb came in second with a healthy proportion of the votes, in a result which saw him fulfil his pledge earlier in the evening to give the Tories "a night to remember".
In 2010, the party received won 8,979 votes.
The Lib Dems, represented by Robin McGhee, took a hammering with just 1,962 of the votes - a huge drop from the 6,872 votes they won in 2010.
They did, however, scrape past the Green Party and UKIP who got 1,765 votes and 1,557 votes respectively.
The Greens warmly welcomed their result which has more than doubled since the 2010 election when they clinched just 753 votes.
Lady Borwick said: "I'm honoured to be elected.
"My immediate goals now depend on who is in government, but if we stay in power then I will continue with the good initiatives we've already started - particularly the work with troubled families.
"Kensington is not just home to the rich and famous. I live here and grew up here. I know there's a lot of people here who need help. I will make sure they get everything they need.
"I will become a good constituency MP and represent the concerns of the people of Kensington.
"The key areas are the best health provision, excellent schools and housing.
"I'm a seven-day-a-week councillor. I do not disappear off to Scotland every weekend. I'm going to make sure I am here for the people as much as possible."