LibreOffice Calc
Definition
This answer assumes the format is a .txt file with tab-separated values.
Requirements
- Available on OS X ✓
- Order according to values ✓
- Insert or move columns around ✓
Bonus
- Free ✓
- Available on Windows and Linux ✓
Demo
Let's start with a file named tsv.txt
:
LASTNAME DOB
CHOP 1985-10-24
DOE 1942-04-20
SANTA 1337-12-25
Open the file
First, I need to open it in LibreOffice Calc. Trying to open it from LibreOffice will trigger the Writer. Instead, I had to right-click the file and choose Open with1.
Calc came up with this window, I only made sure the tabs were checked as separators.

Insert a column
Right click the header of the column where you want to insert one and click Insert Columns Left
.

A new column is added. Fill it and save (Ctrl + S). Now tsv.txt
's content is the following:
LASTNAME FIRSTNAME DOB
CHOP Cyrille 1985-10-24
DOE Jane 1942-04-20
SANTA Nick 1337-12-25
Sort data
Select the range to sort, go to Data > Sort
and set your parameters:

Save again, and admire your file:
LASTNAME FIRSTNAME DOB
SANTA Nick 1337-12-25
DOE Jane 1942-04-20
CHOP Cyrille 1985-10-24
Other functions?
Basically any data manipulation you can do with a spreadsheet, you can do with Calc on your TSV file. This should meet all your needs.
Alternatives
I think most of the commonly used spreadsheet tools can do just as well. Excel has similar functionalities.
1 I made the demo using Ubuntu, but I guess most of it is easy to transpose to OS X. This link shows how to open a TSV txt file in Calc.