How to Capture Parts of a Long String

Try this in your formula text field.

"First Name: "&Part([String], 2, "_")&"<br>
Last Name: "&Part([String], 4, "_")&"<br>
Job: "&Part([String], 6, "_")

This worked when I tested with your example.  Make sure to enable html so you get the line breaks

Sorry I wasnt clear...
each section would be its own formula text field.

First Name would be its own formula text field and i want it to return "John"
Last Name would be its own formula text field and it would return "Smith"

I also want the format of the string not to matter.. meaning I could pass in the string 

"Job_Programmer_LastName_Smith_FirstName_John" and it would return the same results

... I suspect that is going to be very difficult and likely impossible with native QuickBase.  You will need a non native script.

>... I suspect that is going to be very difficult and likely impossible with native QuickBase. 

It is simple:

Formula for [First Name] =

If(
  Part([String], 1, "_") = "FirstName", Part([String], 2, "_"),
  Part([String], 3, "_") = "FirstName", Part([String], 4, "_"),
  Part([String], 5, "_") = "FirstName", Part([String], 6, "_")
)

Formula for [Last Name] =

If(
  Part([String], 1, "_") = "LastName", Part([String], 2, "_"),
  Part([String], 3, "_") = "LastName", Part([String], 4, "_"),
  Part([String], 5, "_") = "LastName", Part([String], 6, "_")
)

Formula for [Job] =

If(
  Part([String], 1, "_") = "Job", Part([String], 2, "_"),
  Part([String], 3, "_") = "Job", Part([String], 4, "_"),
  Part([String], 5, "_") = "Job", Part([String], 6, "_")
)

Yes, in fact that was simple!  I missed that solution.

Oh where is your imagination Mark....

//Break the individual parts out
var text PartOne=Part([String], 1, "_")&Part([String], 2, "_");
var text PartTwo=Part([String], 3, "_")&Part([String], 4, "_");
var text PartThree=Part([String], 5, "_")&Part([String], 6, "_");
//Conditional to find the first name in the string
var text FirstName=If(Contains($PartOne, "First"), "First Name: "&Part([String], 2, "_"), 
If(Contains($PartTwo, "First"), "First Name: "&Part([String], 4, "_"),
If(Contains($PartThree, "First"), "First Name: "&Part([String], 6, "_"),
"No First Name")));
//Conditional to find the last name in the string
var text LastName=If(Contains($PartOne, "Last"), "Last Name: "&Part([String], 2, "_"), 
If(Contains($PartTwo, "Last"), "Last Name: "&Part([String], 4, "_"),
If(Contains($PartThree, "Last"), "Last Name: "&Part([String], 6, "_"),
"No Last Name")));
//Conditional to find the job in the string
var text Job=If(Contains($PartOne, "Job"), "Job: "&Part([String], 2, "_"), 
If(Contains($PartTwo, "Job"), "Job: "&Part([String], 4, "_"),
If(Contains($PartThree, "Job"), "Job: "&Part([String], 6, "_"),
"No Job")));
//Combine them into the desired list
List("<br>", $FirstName, $LastName, $Job)

It works with any and all combos.  Just as long as the string is divided by the "_" and maintains the format you proposed