Born in Santa Monica, California, Gaechter graduated from Antelope Valley High School in Lancaster, where he was a standout in track and played as a halfback in football.
Because of grades he transferred to Clark College in Vancouver, Washington, where he competed in the long jump, the 100, 200, low and high hurdles, and the relay team.
That year during a track meet at the University of Washington in Seattle, he recorded his fastest time with 9.4 seconds in the 100-yard dash at Husky Stadium.
In 1962, Gaechter with teammates Mel Renfro, Jerry Tarr, and Harry Jerome, ran the third leg on the University of Oregon's world record setting team, in the 4x110 yard relay.
[3] Gaechter was signed by the Dallas Cowboys in 1962 as an undrafted free agent and became the starting left cornerback as a rookie because of injuries.
Gaechter had been a mainstay on the Cowboys defense for most of the 1960s, until rupturing his Achilles tendon at the end of the 1969 season, in the third place Playoff Bowl loss to the Los Angeles Rams in January 1970.