After progressing through the Walsall youth system his first taste of senior action came on September 18^th 1993, when he came on as a substitute, replacing Richard Knight in the 1-0 league win at Chesterfield.  Three weeks later the midfielder made his first start for the club, wearing the unusual number 9 shirt in the home win against Gillingham.  On that day there were two Walsall youngsters making their first team debuts James Walker and Martin Butler, the latter replaced Keister in the second half.  By the end of his first campaign of first team actiom Keister had made 26 appearances with his only goal winning the three home points against Torquay. 

Keister made 11 appearances in our 1994/5 promotion season and took part in 25 games the following season.  It was in the 1996/7 campaign that Keister made the bulk of his Walsall appearances, in a season that will mainly be remembered for Adrian Viveash scoring 10 goals, and for being Chris Nicholl's last in charge. 

Keister suffered a cruciate ligament injury that ruled him out for nearly a year.  He returned to action in the 1999/2000 season for two games, but Walsall were now competing in the Championship and appearances became few and far between.  The popular  midfield figure joined Siggi Eyjolfsson  in becoming a new loan signings for Ian Atkins on his first day as Chester manager.  He returned briefly before then leaving to join Shrewsbury on a two month loan contract, a move which was funded by the Shrewsbury's Independent Supporters Association. 

In August 2001 Keister joined up with Margate where he was extremely unfortunate to suffer another cruciate ligament injury, this time in his other leg.  He bounced back and managed to win international honours with Sierra Leone, achieving the unlikely distinction of being the only current international in the conference. The contrast between club and country could hardly have been greater, as he would go from playing in front of around 1000 for his club, to playing before 50,000 for his country, in less than a week. Were it not for his injuries there is little doubt that Keister could have prolonged his League career; a combative, batting midfielder, he is the type every lower-league club needs. 

At Margate Keister found the goals easier to come by, scoring 15 times in 86 games, but kept his comvative part of his game seeing 27 yellow cards and 3 reds.  In August 2006 Keister joined Dover