In 1966 he became the first basketball player to be named the Icelandic Sportsperson of the Year.
[4] Kolbeinn spent his entire career with KR, playing a total of 383 games for the club.
[5][1] On 1 December 1977 Kolbeinn ruptured his left achilles tendon in a game against Valur.
[8] In 1966 he made two free throws in the final seconds of Iceland's game against Denmark, giving them victory and the bronze in the 1966 Nordic Championships.
[9] Kolbeinn is the father of former Icelandic national team player Páll Kolbeinsson.