[1] In July 2014, he represented the Blue Bulls at the premier high school rugby union competition in South Africa, the Under-18 Craven Week held in Middelburg.

[3] After the Craven Week tournament, he was also selected in the 2014 South African Schools squad that played matches against their counterparts from France, Wales and England in August.

[7] De Beer made his first class debut for the Blue Bulls during the 2015 Vodacom Cup competition.

[8] He started his first match the following week, kicking seven points in the Blue Bulls' 40–21 win over the Griffons in Pretoria.

[9] Despite initially not being named in a 37-man South Africa Under-20 training squad[10] or playing for them in warm-up matches against a Varsity Cup Dream Team[11] or two matches during a tour to Argentina,[12] he was named in the final squad for the 2015 World Rugby Under 20 Championship.