He doesn't look satisfied with things, and you can'f blame him. Four months in office, and bang. Wikipedia notes:
As usual, the votes had barely been counted when office-seekers besieged Garfield. There were at this point over 100,000 federal government employees, most of whom expected to be replaced when a new administration took over; the President-elect described the situation as "a barrage of fear and greed." Garfield was convinced the only answer was some type of civil service reform.
Wise move. Maintain continuity. One might lose influence, but the public would be reassured.
Except for Charlies Guiteau, of course. Wikipedia on the conclusion of his trial for murdering Garfield:
After the guilty verdict was read, Guiteau stepped forward, despite his lawyers' efforts to tell him to be quiet, and yelled at the jury saying "You are all low, consummate jackasses!" plus a further stream of curses and obscenities before he was taken away by guards to his cell to await execution.
While being led to his execution, Guiteau was said to have continued to smile and wave at spectators and reporters, happy to be at the center of attention to the very end. He notoriously danced his way to the gallows and on the scaffold as a last request, he recited a poem he had written during his incarceration which he called "I am Going to the Lordy."
The poem survived both Garfield and Guiteau. As even doggeral is wont to do.