In 1910 the French, who had played in four of the tournaments up to that point, officially joined the competition and coined the phrase "Five Nations".  England won the first championship of the new era, with the Welsh achieving the first Grand Slam the following year. The competition was suspended during World War I (1914-18).  In 1931, France were ejected from the tournament, which reverted to being the "Home Nations" from 1932 through to 1939. The competition was suspended again during World War II (1939-1945).  With France back in the competition, the Five Nations resumed in 1947, with a shared victory for England and Wales.  France won their first shared title in 1954, and their first outright title in 1959.

By the 1970s the Five Nations Championship had become the pre-eminent series in Northern hemisphere rugby union with matches becoming all-ticket affairs, gaining huge popularity and a large television audience. The 1972 tournament was not finished after Scotland and Wales refused to play in Dublin. The season after was unique for a five-way tie, with every nation having won and lost two games. The 1970s marked the golden age for Welsh rugby; winning three Grand Slams and one Triple Crown during the decade. Until 1993, there was no tangible reward for winning the Five Nations championship.  The Trophy was presented for the first time in 1993 to France.

France were the first winners of the new trophy, followed by Wales and then England. Scotland's first success came in season 1998-99; Ireland have yet to win it. Scotland was the last nation to win the Five Nations Trophy as such because Italy joined the competition in 2000 and the tournament became known as the "Six Nations Championship".  England were the first nation to win the trophy under the new format, winning the 2000 competition.

Prior to 1994, teams equal on points shared the championship. After that date, ties were broken by considering the points difference of the teams. In 2005 Wales won the Grand Slam, becoming the first team ever to win a Grand Slam playing more games away than at home. This was the last Grand Slam to date.

In 2006, France won the competition on points difference over Ireland. Ireland received the consolation prize of the Triple Crown Trophy, presented for the first time that year. Italy once more collected the Wooden Spoon, but showed considerable improvement over past years, earning a first-ever competition point away from home in a draw against Wales.

In 2007, France again won on points difference, after four teams had at least a mathematical chance of topping the table going into the final week. The Italians had their first away win of the tournament beating Scotland in Edinburgh. It was also the first time they won two of their matches as they went on to beat Wales in Rome. Scotland won the wooden spoon and Ireland won the Triple Crown for the second straight year and third time in four years.