De Boer was born in
Hollum, on the
West Frisian island of
Ameland. He won six Dutch national titles in the long jump and set six Dutch records. The longest jump, 7.37m reached in 1928, would only be broken in 1951. De Boer was also a member of the Dutch
4 x 100 metres relay team that set a national record in 1926. This record was broken in 1934 by a relay team that included
Chris Berger and
Tinus Osendarp. He won the British
AAA Championships title in the long jump event at the
1928 AAA Championships and the
1931 AAA Championships. Shortly after the 1928 AAAs, he represented the Netherlands at his second Olympic Games in Amsterdam, Netherlands. He worked as an office clerk, but later became a cameraman for Dutch
cinema newsreels. He died in
Rijswijk, near
The Hague, in 1982. ==Honours==