A 6-foot-9-inch (2.06 m), 277-pound (126 kg) forward/center, Ketner played college basketball at the University of Massachusetts Amherst, and was selected by the Chicago Bulls with the 49th overall pick (second round) of the 1999 NBA draft.

Ketner played in two National Basketball Association (NBA) seasons for three teams: Chicago Bulls (1999–2000), Cleveland Cavaliers (1999–2000) and Indiana Pacers (2000–01).

He played in the Continental Basketball Association (CBA) for the Fort Wayne Fury and Idaho Stampede.

[1] On January 1, 2005, while standing outside of a nightclub talking to associates, Lari was shot eight times by an unknown person, ultimately ending his basketball career.

[2][3] After being diagnosed with cancer, Ketner completed the three courses needed to receive his bachelor's degree from University of Massachusetts Amherst.