A lively opening to the encounter saw the hosts have the first major chance when Mikkel Kaufmann found time and space in the box, but he went for power over placement and Kevin Trapp was able to beat the ball away.
Frankfurt slowly grew into the game from there, and made their pressure count midway through the half.
A delightful through ball from Nathaniel Brown released Omar Marmoush through on goal and the Egyptian kept his cool to drill the ball home at the near post.
Marmoush almost doubled his tally moments later as he sped towards goal, but he went for an audacious effort with the outside of his foot and failed to trouble Kevin Muller.
The hosts pushed before the interval but couldn’t create anything clear-cut, and they were hit with a sucker punch shortly after the restart.
Fares Chaibi was introduced at the break and only needed four minutes to make an impact as the ball broke to him on the edge of the box and he calmly slotted into the bottom corner to make it 2-0.
That goal may have made it an uphill task for Heidenheim, but it was game over nine minutes later when Marmoush showed his pace to get in behind before a calm finish into the far corner made it 17 goals in 19 appearances for the season for the Eagles’ marksman.
The hosts looked defeated by that stage, and things almost got worse as Marmoush hunted his hat-trick, but he dragged a shot wide before forcing a save from Muller.
The Egyptian forward then spurned a third chance to take home the match ball, but a Frankfurt fourth arrived in stoppage time as substitute Hugo Ekitike sealed a seventh successive victory for the Eagles, who continue to impress on the domestic and European stage.
The same can't be said of opponents Heidenheim, who are now winless in seven league matches and in the relegation zone as a result.
Flashscore Man of the Match: Omar Marmoush (Eintracht Frankfurt)