Nicholas was born on 1 April 1985, in Meyrin, a commuter town near Geneva, Switzerland; The first child and son of Princess Elena of Romania and her first husband Robin Medforth-Mills and also the second grandchild of King Michael I of Romania and his wife Queen Anne. He was baptised in the Orthodox faith, his godparents being: Queen Anne (his maternal grandmother) and Crown Princess Margareta of Romania (his maternal aunt).
He was followed by a sister, Elisabeta-Karina (born 1989).
Until the age of 4, Nicholas with his sister and parents lived at the Romanian royal family's residence in Versoix, Switzerland. The family moved to England in 1989 where they took up residence at Flass Hall, Esh Winning in County Durham.
At age 5 he joined the Beaver Scouts.
During his childhood, he developed an interest in cars, an interest shared with King Michael I; Nicholas has had the opportunity to drive more than 100 cars, not to mention planes and boats. During holidays in Versoix, Switzerland with his maternal grandparents, Nicholas spent hours in his grandfather's garage, watching him maintaining his jeep collection. In an interview with historian Filip-Lucian Iorga, Nicholas recalled the time spent with King Michael, and how His Majesty allowed him to drive one of his cars, a Ford which once belonged to General George S. Patton; the vehicle was given to his grandfather by Queen Anne's paternal uncle Prince Felix of Bourbon-Parma as a gift. He also recalled spending time with Queen Anne, at Versoix where they used to fish and play golf together.
As well as his maternal cousins, Nicholas was explained about his family's lineage, who they were and what duty they had towards Romania.
As a descendant of Queen Victoria of the United Kingdom and King Christian IX of Denmark he regularly met with many of his extended royal relatives.
He attended Argyle House School, Sunderland, England which he left in 1999 with 8 GCSE's of English Language, English Literature, Mathematics, Science (Chemistry, Biology and Physics), French, German, Information Technology and also Geography.
In 1999, he enrolled with Shiplake College, Henley-on-Thames, England where he left with 3 A-level's of French, Business Sciences and Physical Education. During this time he also took part in the Duke of Edinburgh's Award.
Before enrolling for university he took a 5 year "Gap year", where:In 2004, before enrolling for university, Nicholas was assistant leader of an expedition to South Africa, Namibia, Botswana and Zimbabwe.
In 2005, he lived in Kenya for four months and joined an expedition to Madagascar.
In 2006, he was employed in Kenya as a rafting trainer for the British Armies.
As his passions included traveling and sports, he shortly worked for World Challenge Expeditions.
From 2009 to 2012, Nicholas attended a Management course at the Royal Holloway, University of London.
Nicholas' first major official appearance in Romania was on 19 April 1992 on Easter Day along with his grandparents King Michael I and Queen Anne and also with his mother and her second husband Alexander Nixon where they were met by hundreds of thousands of supporters; he and his mother waved the royal flag from a balcony in Revolution Square.
He came again for the second time on Christmas Day 1997 when the entire royal family set foot in Romania for the first time after nearly 5 decades of exile.
In 2002 Nicholas visited Romania for the third time; he stayed at Elisabeta Palace. During this visit he started to consider his role as a member of the royal family, which step-by-step required a fundamental transformation in him.
In 1997, Romanian monarchists intended to ask Michael to designate a male heir-presumptive from the House of Hohenzollern, in keeping with the rules of the last royal constitution which were based on agnatic primogeniture and "Salic law"; The monarchists eventually agreed on a compromise and requested him to designate a male rather than female heir-presumptive, in the person of Nicholas. However, under the influence of Queen Anne, Michael rejected the monarchists' request and at the end of 1997, he designated Princess Margareta, as heir presumptive in keeping with the European Convention on Human Rights, which meant Nicholas would only succeed to the headship of the royal family after the deaths of King Michael, Crown Princess Margareta and his mother.
In 2005, Michael told Nicholas that should he want, he could choose to have the chance of becoming a "Prince of Romania" which would mean assuming responsibility in a conscious manner by starting to work for the country. Gradually after many talks and deep consideration Nicholas decided that he would devote his life to Romania.
On 30 December 2007 the press office of King Michael announced that Nicholas would receive the title "Prince of Romania" with the style of "Royal Highness", coming into effect on Nicholas's 25th birthday. On 1 April 2010, by virtue of his new title, he became a member of the Romanian royal family and was also decorated with the Nihil Sine Deo, the highest of royal decorations at the time.
In February 2008, Nicholas stated in an interview with the Romanian daily newspaper Cotidianul that if the Romanian people asked him to become king, he would not refuse.
In September 2012, after his gap year and university studies, he moved to Romania to undertake more of the royal family's public activities.
On 1 August 2015, former King Michael of Romania signed a document removing the title Prince of Romania and the qualification of Royal Highness from his grandson, Nicholas. Nicholas has also been removed from the line of succession. The former king took the decision that the royal family on the consideration that Romania needed a ruling marked by modesty and moral principles, respect and always thinking of others after the "reign and life" of his eldest daughter, Crown Princess Margarita. The former king hopes that "Nicholas will find in future years a suitable way to serve the ideals and use the qualities that God gave him". Nicholas's mother, Princess Helen, received notification of the former king's decision in a personal letter.
The move "has stunned Romanians" and "sparked speculation that a jealous relative had sought to edge Nicholas out of the succession."
Since the beginning of 2008, Nicholas has become more and more involved in the public life of Romania, taking part, for instance, at the 2008 UNITER theater gala and in visits throughout the country with his Aunt, Crown Princess Margareta and his uncle, Prince Radu.1 April 2010 – 1 August 2015: His Royal Highness Prince Nicholas of Romania
1 August 2015 – present: Mr. Nicholas de Roumanie Medforth-Mills
House of Romania: Knight Grand Cross of the Order of the Crown
House of Romania: Knight of the Decoration of the Custodian of the Romanian Crown, 1st Class
House of Romania: Knight of the Decoration of Nihil Sine Deo