Ifwersen then switched codes to rugby league, joining the North Shore Albions where he debuted for them on the 3 May, 1913. He scored a try in a 13-10 win over the reigning champions Newton Rangers. He played for Auckland before representing his club and made the 1913 New Zealand tour of Australia. The following year he joined the newly formed Grafton Athletic senior team. He performed outstandingly for them and led the competition in scoring in 1914 with 66 points and in 1915 with 78 points which greatly assisted Grafton in winning their first ever championship. Indeed he scored 146 of their 193 points in those two seasons. In the 1916 season he once again led the league in scoring with 56 points however the 1917 season was to be a frustrating one with his Grafton team struggling for playing numbers and they were forced to default matches before dropping out of the competition. In 1918 though he again was prolific, scoring 4 tries, and kicking 27 goals for 66 points to lead the league in scoring for a remarkable 5th season out of six. He also represented Auckland in their first match in a number of years and he scored 2 tries and kicked 4 goals in a 45-9 win over Canterbury in front of 10,000 spectators at the Auckland Domain.
World War
Ifwersen was part of the advance to Samoa at the start of the war before rejoining Grafton for the 1915 season. He joined the twenty-eighth draft which mobilised for camp on April 10, 1917. It is unclear where he served as he was frequently in Auckland playing for Grafton throughout the war and his war record like most others who served during World War I is lacking in specific details.
Return to league
Despite serving in the armed forces Ifwersen still managed to turn out for Grafton at stages in every year of the war. He again made the New Zealand side. He captained the Kiwis against the 1920 Great Britain Lions tourists. Ifwersen also captained the side in four Test matches in 1919.
In 1921 Ifwersen switched codes, playing rugby union. He immediately returned to the rep team, captaining the combined Auckland-North Auckland side against South Africa in his first game back and scoring the only try. Ifwersen played in one test match for the All Blacks during the 1921 South Africa tour of the country. At some point after this the New Zealand Rugby Union decided that reinstated players could not represent New Zealand again and although Ifwersen was eligible to play for Auckland he could not gain higher honours again. Indeed his playing in an All Black trial match in 1924 caused some controversy with the rugby union seeking to know why he had been allowed to take the field. He had not been named in the original side but had gone on to replace and injured player Ifwersen continued to play for Auckland between 1921 and 1938.
Later years
Ifwersen died in Auckland on 19 May 1967, having suffered considerably from football injuries during his old age.
Legacy
Ifwersen was inducted into the New Zealand Rugby League's Legends of League in 2000. He was the first New Zealander to represent New Zealand in rugby league before rugby union. This accomplishment would be unmatched until almost 90 years later by Sonny Bill Williams.
