Career
His personal best for the discipline was 21.09 m (69 ft 21⁄4 in), a former national record. He twice represented his country at the Summer Olympics and was the gold medallist at the European Athletics Indoor Championships in 1977 (Iceland"s first medallist at the competition). Halldórsson was affiliated with KR Reykjavík sports club during his career.
He also made a winning guest appearance at the 1974 Scottish Championships.
Internationally, Halldórsson had four consecutive wins at the European Cup qualifiers from 1975 to 1981, including a meet record of 20.54 m (67 ft 41⁄2 in). His first major competition was the 1974 European Athletics Championships, but the 25-year-old Halldórsson failed to make it out of the qualifying round.
After a ninth-place finish at the 1976 European Athletics Indoor Championships, he entered the 1976 Summer Olympics, where he came 15th in the qualifying round. He topped the podium at the 1977 European Athletics Indoor Championships, taking the first and only continental gold medal of his career.
Later that year he threw a personal best of 21.09 m (69 ft 21⁄4 in), which ranked him fourth in the world and was an Icelandic national record (he remains the country"s second best shot putter after Pétur Guðmundsson).
His season"s best of 20.95 m (68 ft 83⁄4 in) again ranked him in the top five globally. There were no major events for him to aim for in the 1979 season, but his throw of 20.69 m (67 ft 101⁄2 in) that year ranked him in the global top ten. His highest placing at a world-level event came at the 1980 Moscow Olympics, where he threw 19.74 m (64 ft 9 in) in qualifying, then 19.55 m (64 ft 11⁄2 in) in the final for tenth place.
The latter performance was a metre down on his best that season.
In his final top level international competition he was sixth at the 1981 European Athletics Indoor Championships.