This is a list of seasons completed by the Harrisburg Senators of the Eastern League. This list documents the records and playoff results for all seasons the Senators have completed since their first inception in 1924 through 1935, and their second inception since 1987.
| Year (affiliation) | Wins | Losses | Winning Pct. | GB (Division Standing) | Manager | |
|---|---|---|---|---|---|---|
| 1924 (Independent) | 70 | 60 | .539 | -15.5 (4th out of 8) | Steve Yerkes/Mickey LaLonge/Glen Killinger | |
| 1925 (Independent) | 61 | 69 | .469 | -15 (6th out of 8) | Rankin Johnson, Sr. | |
| 1926 (Independent) | 47 | 84 | .359 | -35.5 (8th out of 8) | Rankin Johnson/Joe Lightner | |
| 1927 (Independent) | 87 | 51 | .630 | +6 (1st out of 8) | Win Clark | |
| 1928 (Independent) | 82 | 54 | .603 | +1 (1st out of 8) | Glen Killinger | |
| 1929 (Independent) | 75 | 62 | .547 | -7 (3rd out of 8) | Johnny Tillman | |
| 1930 (Independent) | 70 | 69 | .504 | -9.5 (4th out of 8) | Johnny Tillman | |
| 1931 (Independent) | 83 | 56 | .597 | +3 (1st out of 8) | Joe Cobb/Eddie Onslow | |
| 1932 (Boston Braves) | 74 | 66 | .529 | -4.5 (2nd out of 8) | Eddie Onslow | |
| 1933 (Boston Braves) | 60 | 76 | .441 | -20 (7th out of 8) | Eddie Onslow | |
| 1934 (Boston Braves) | 60 | 75 | .444 | -16.5 (8th out of 8) | Leslie Mann | |
| 1935 (Boston Braves) | 59 | 77 | .434 | -22.5 (6th out of 8) | Art Shires | |
| ORIGINAL SENATORS TOTAL | 828 | 799 | .509 |
| Year (affiliation) | Wins | Losses | Winning Pct. | GB (Division Standing) | Manager | |
|---|---|---|---|---|---|---|
| 1987 (Pittsburgh Pirates) | 77 | 63 | .550 | -11 (2nd out of 8) | Dave Trembley | |
| 1988 (Pittsburgh Pirates) | 65 | 73 | .471 | -15.5 (7th out of 8) | Dave Trembley | |
| 1989 (Pittsburgh Pirates) | 71 | 65 | .522 | -19 (2nd out of 8) | Dave Trembley | |
| 1990 (Pittsburgh Pirates) | 69 | 69 | .500 | -9.5 (5th out of 8) | Marc Bombard | |
| 1991 (Montreal Expos) | 87 | 53 | .621 | +6 (1st out of 8) | Mike Quade | |
| 1992 (Montreal Expos) | 78 | 59 | .569 | -1.5 (3rd out of 8) | Mike Quade | |
| 1993 (Montreal Expos) | 94 | 44 | .681 | +19 (1st out of 8) | Jim Tracy | |
| 1994 (Montreal Expos) | 88 | 51 | .633 | +5.5 (1st out of 5 in Southern Division) | Dave Jauss | |
| 1995 (Montreal Expos) | 61 | 80 | .433 | -11.5 (5th out of 5 in Southern Division) | Pat Kelly | |
| 1996 (Montreal Expos) | 74 | 68 | .521 | -12 (2nd out of 5 in Southern Division) | Pat Kelly | |
| 1997 (Montreal Expos) | 86 | 56 | .606 | +11 (1st out of 5 in Southern Division) | Rick Sofield | |
| 1998 (Montreal Expos) | 73 | 69 | .514 | -8.5 (2nd out of 5 in Southern Division) | Rick Sweet | |
| 1999 (Montreal Expos) | 76 | 66 | .535 | -9.5 (2nd out of 6 in Southern Division) | Doug Sisson | |
| 2000 (Montreal Expos) | 76 | 67 | .531 | -9.5 (2nd out of 6 in Southern Division) | Doug Sisson | |
| 2001 (Montreal Expos) | 66 | 76 | .465 | -18 (4th out of 6 in Southern Division) | Luis Dorante | |
| 2002 (Montreal Expos) | 79 | 63 | .556 | -14.5 (2nd out of 6 in Southern Division) | Dave Huppert | |
| 2003 (Montreal Expos) | 60 | 82 | .423 | -28.5 (6th out of 6 in Southern Division) | Dave Machemer | |
| 2004 (Montreal Expos) | 52 | 90 | .366 | -33.5 (6th out of 6 in Southern Division) | Dave Machemer | |
| 2005 (Washington Nationals) | 64 | 78 | .451 | -20 (5th out of 6 in Southern Division) | Keith Bodie | |
| 2006 (Washington Nationals) | 67 | 75 | .472 | -20 (5th out of 6 in Southern Division) | John Stearns | |
| 2007 (Washington Nationals) | 55 | 86 | .390 | -26.5 (6th out of 6 in Southern Division) | Scott Little | |
| 2008 (Washington Nationals) | 73 | 69 | .514 | -11 (3rd out of 6 in Southern Division) | John Stearns | |
| 2009 (Washington Nationals) | 70 | 72 | .493 | -19 (5th out of 6 in Southern Division) | John Stearns | |
| 2010 (Washington Nationals) | 77 | 65 | .542 | -5 (2nd out of 6 in Western Division) | Randy Knorr | |
| 2011 (Washington Nationals) | 80 | 62 | .563 | +4 (1st out of 6 in Western Division) | Tony Beasley | |
| 2012 (Washington Nationals) | 64 | 78 | .451 | -18.5 (5th out of 6 in Western Division) | Matthew LeCroy | |
| 2013 (Washington Nationals) | 77 | 65 | .542 | +1 (1st out of 6 in Western Division) | Matthew LeCroy | |
| 2014 (Washington Nationals) | 53 | 89 | .373 | -26 (6th out of 6 in Western Division) | Brian Daubach | |
| 2015 (Washington Nationals) | 67 | 75 | .472 | -12 (5th out of 6 in Western Division) | Brian Daubach | |
| 2016 (Washington Nationals) | 76 | 66 | .535 | -1.5 (3rd out of 6 in Western Division) | Matthew LeCroy | |
| 2017 (Washington Nationals) | 60 | 80 | .429 | -14 (6th out of 6 in Western Division) | Matthew LeCroy | |
| 2018 (Washington Nationals) | 72 | 65 | .526 | -5.5 (3rd out of 6 in Western Division) | Matthew LeCroy | |
| 2019 (Washington Nationals) | 76 | 63 | .547 | -1.5 (2nd out of 6 in Western Division, 1st Half Division Winner) | Matthew LeCroy | |
| 2021 (Washington Nationals) | 42 | 76 | .356 | −30.5 (6th out of 6 in Southwestern Division) | Tripp Keister | |
| 2022 (Washington Nationals) | 52 | 85 | .380 | −27.5 (6th out of 6 in Southwestern Division) | Tripp Keister | |
| 2023 (Washington Nationals) | 59 | 77 | .434 | −15.5 (6th out of 6 in Southwestern Division) | Delino DeShields | |
| CURRENT SENATORS TOTAL | 2516 | 2520 | .500 | |||
| ALL TIME TOTAL | 3344 | 3319 | .502 |
- in GB is behind, + in GB is aheadBold years are Eastern League Championship years
| Playoff Results | ||||
|---|---|---|---|---|
| Year | Round | Opponent | Result | |
| 1987 | Semi-Finals | vs. Reading | 3-2 | |
| Finals | vs. Vermont | 3-1 | ||
| 1989 | Semi-Finals | vs. Canton-Akron | 3-2 | |
| Finals | vs. Albany | 1-3 | ||
| 1991 | Semi-Finals | vs. Canton-Akron | 3-1 | |
| Finals | vs. Albany | 1-3 | ||
| 1992 | Semi-Finals | vs. Canton-Akron | 1-3 | |
| 1993 | Semi-Finals | vs. Albany-Colonie | 3-1 | |
| Finals | vs. Canton-Akron | 3-2 | ||
| 1994 | Semi-Finals | vs. Bowie | 3-2 | |
| Finals | vs. Binghamton | 1-3 | ||
| 1996 | Semi-Finals | vs. Trenton | 3-1 | |
| Finals | vs. Portland | 3-1 | ||
| 1997 | Semi-Finals | vs. Bowie | 3-2 | |
| Finals | vs. Portland | 3-1 | ||
| 1998 | Semi-Finals | vs. Akron | 3-1 | |
| Finals | vs. New Britain | 3-1 | ||
| 1999 | Semi-Finals | vs. Erie | 3-1 | |
| Finals | vs. Norwich | 3-2 | ||
| 2000 | Semi-Finals | vs. Reading | 0-3 | |
| 2002 | Semi-Finals | vs. Akron | 3-2 | |
| Finals | vs. Norwich | 2-3 | ||
| 2010 | Semi-Finals | vs. Altoona | 1-3 | |
| 2011 | Semi-Finals | vs. Richmond | 0-3 | |
| 2013 | Semi-Finals | vs. Erie | 3-1 | |
| Finals | vs. Trenton | 0-3 | ||
| 2019 | Semi-Finals | vs. Bowie | 1-3 | |
| PLAYOFF RECORD | .522 Win Pct. | 59-54 |