He served as the head coach at Austin College in Sherman, Texas from 1984 to 1993 and at Northwest Missouri State University from 1994 until his retirement after the 2010 season.

Tjeerdsma coached at Sioux Center (Iowa) High School and in 1972 won the very first Class 2A State football championship.

The Red Raiders earned four trips to the NAIA Division II Playoffs while Tjeerdsma was there, including a national championship in 1983.

His track and field teams won three Tri-State Conference titles and five consecutive NAIA District 15 indoor championships.

Tjeerdsma guided Austin College to three Texas Intercollegiate Athletic Association championships in 1984, 1985 and 1988 and made two trips to the NAIA Division II playoffs.

In 2005, the Bearcats were a Cinderella team being ranked 22nd at the start of the playoffs, but won four games on the road until reaching the finals where they faced Grand Valley State.

The St. Louis Rams donated their private jet to the team to fly the Bearcats to the championship game in Florence, Alabama.

When Tjeerdsma began his run, Northwest could not play some home playoff games to which it was entitled because of poor conditions at Rickenbrode Stadium.

[2] In June 2011 he announced that he would join the development team in the Austin College Institutional Advancement Division in the fall of 2011, leading fundraising efforts for athletics enhancement.