This article will assume you have a Unity app or game that has already been built into a signed .apk file and is ready to be deployed to the Google Play Store.
Here is one option of accomplishing this if you haven't already:

Creating an account

The first step to publishing an app on the Google Play store is to create a developer account. You can use any existing gmail account, or you can create a new one specifically for this purpose (recommended). Creating a Google Play developer account comes with a one time fee of $25. After selecting a gmail account, providing some basic information, and paying the fee then you are ready to get started publishing your first application!
Here is a helpful guide with more details:

Creating an application

After creating an account you should be brought to the Google Play developer console. Here you can view any created applications, manage your account, or create a new application. We will want to click the blue Create Application button.

create-application

Once the dialog pops up select your desired language and give your application a name.

There are a few things that are needed for an application to meet the requirements to be able to be put out onto the Google Play store. If you try to publish an application without these things in place it will fail. All of the required items can be found under the Store Presence tab on the left-hand menu of your application.

store-listing-requirements

Here is a summary of the bare minimum:

Requirements

  • Store Listing
    • Title - 50 character limit
    • A short description - 80 character limit
    • A long description - 4000 characters limit
    • 2 screenshots - Min. 320px/side Max. 3840px/side
    • Application type - Application or Games
    • Category - Many choices
    • Hi-res icon - [512x512] 32-bit PNG (with alpha)
      Icon displayed in the Google Play Store list of applications
    • Feature Graphic [1024x500] JPG or 24-bit PNG (no alpha)
      Displayed at the top of the Google Play Store
  • Content rating questionnaire
  • A valid email address
  • Pricing & Distribution information

Ex. of the Hi-res Icon and Feature Graphic when uploaded to the Google Play Console:

Capture

Ex. of the Hi-res Icon and Feature Graphic as seen on the app inside the Google Play Store

app-store-images-1

You will need to meet all of the requirements before being able to complete the creation of this application. If you do not have these things, you can Save Draft to save your changes and come back to provide these things as you acquire them.

Release Management

Once you have a valid application in the developer console you will be able to start a release. Release Management has a few different options to choose from: Alpha, Beta, or Production.

  • Alpha release is aimed towards getting some very early testers access to the application and can be done with an Open or Closed mode. Closed would be restricted to a specific list of users, while Open would allow the application to be downloaded by the public.
  • Beta release is very similar to Alpha but is typically geared towards a larger set of testers than an Alpha test.
  • Production release is for when you are ready to release a full or complete version of your application and have it live on the Google Play store. If you have a live Alpha or Beta test you can promote those releases to higher environments without having to start from scratch

You can run both an Alpha and a Beta test at the same time but you can't run the same type of test for each. For example you can run a closed Alpha and an open Beta at the same time, but you can't run a closed Alpha and a closed Beta at the same time.

After selecting your desired release the next step is to upload your .apk file. There are a lot of other features that can be tweaked and adjusted to make your application and release exactly the way you want it.

Here is a helpful guide with more details:

Uploading the .apk

After setting up your application and creating a release you are ready to upload your .apk file to the developer console. To upload your .apk you will need to make sure that your .apk has been signed.

After you have a successfully signed and built the .apk, inside the Developer Console expand the Release Management tab then click on App Releases, select your desired track (Internal, Open, Closed, or Production). Inside of this release you will see an option to upload your .apk. If your .apk fails to upload a likely cause is that it was not signed correctly and you may need to go back into Unity to re-sign and build your game. If it uploads successfully you can proceed to adding a version number and some release notes.

app-store-release

If you are satisfied with your changes you can click Save and then Review. This will bring you to the final page to give you a chance to look over your changes one last time before beginning the final rollout process.

app-store-rollout

Application rollouts can take anywhere from 24-48 hours to appear on the store and you will receive a notification inside the developer console when the rollout has been completed and is available on the store.

app-published

Congratulations!

Things to note:

  • When adding testers to your test list be sure to pass them the sign up link or else they will not be able to join your test group

Sources: