Gachkar grew up in Overland Park, Kansas and attended Blue Valley West High School.

As a senior, he was limited by a shoulder injury, but still managed to be a two-way player at running back and linebacker.

As a sophomore, he recovered from four surgeries in the off-season, where he had a rib removed to alleviate blood clotting issues in his right arm and upper body.

Gachkar was selected by the San Diego Chargers in the seventh round (234th overall) of the 2011 NFL draft.

In 2014, he received more playing time due to injuries and defensive coordinator John Pagano rotations at linebacker.

On March 15, 2015, he signed with the Dallas Cowboys a two-year, $5.5 million contract, reuniting with former Chargers special teams coordinator Rich Bisaccia.

[3] As a reserve linebacker, he showed the ability to play all three positions and made Jasper Brinkley expendable.

In the eighth game of the season against the Philadelphia Eagles, he saw extended time in place of Sean Lee who was out with a concussion, while tallying 4 tackles (one for loss).

In the season finale against the Philadelphia Eagles, the Cowboys rested players for the playoffs and Gachkar saw extended playing time, posting 5 tackles (one for loss), 2 quarterback pressures and a half-sack.

The surgeries initially put his football future in doubt, but after rehabilitation, he made it back for the 2008 season without missing a game.