diff --git a/packages/core/__tests__/command.test.ts b/packages/core/__tests__/command.test.ts
index 182e145cb3..da3df23a4e 100644
--- a/packages/core/__tests__/command.test.ts
+++ b/packages/core/__tests__/command.test.ts
@@ -112,6 +112,21 @@ describe('@actions/core/src/command', () => {
       `::some-command prop1=value 1,prop2=value 2,prop3=value 3::${os.EOL}`
     ])
   })
+
+  it('should handle issueing commands for non-string objects', () => {
+    command.issueCommand(
+      'some-command',
+      {
+        prop1: ({test: 'object'} as unknown) as string,
+        prop2: (123 as unknown) as string,
+        prop3: (true as unknown) as string
+      },
+      ({test: 'object'} as unknown) as string
+    )
+    assertWriteCalls([
+      `::some-command prop1={"test"%3A"object"},prop2=123,prop3=true::{"test":"object"}${os.EOL}`
+    ])
+  })
 })
 
 // Assert that process.stdout.write calls called only with the given arguments.
diff --git a/packages/core/__tests__/core.test.ts b/packages/core/__tests__/core.test.ts
index 020f4a51b9..d10e0590d8 100644
--- a/packages/core/__tests__/core.test.ts
+++ b/packages/core/__tests__/core.test.ts
@@ -54,6 +54,16 @@ describe('@actions/core', () => {
     assertWriteCalls([`::set-env name=my var2::var val%0D%0A${os.EOL}`])
   })
 
+  it('exportVariable handles boolean inputs', () => {
+    core.exportVariable('my var', true)
+    assertWriteCalls([`::set-env name=my var::true${os.EOL}`])
+  })
+
+  it('exportVariable handles number inputs', () => {
+    core.exportVariable('my var', 5)
+    assertWriteCalls([`::set-env name=my var::5${os.EOL}`])
+  })
+
   it('setSecret produces the correct command', () => {
     core.setSecret('secret val')
     assertWriteCalls([`::add-mask::secret val${os.EOL}`])
@@ -104,18 +114,35 @@ describe('@actions/core', () => {
     assertWriteCalls([`::set-output name=some output::some value${os.EOL}`])
   })
 
-  it('setFailure sets the correct exit code and failure message', () => {
+  it('setOutput handles bools', () => {
+    core.setOutput('some output', false)
+    assertWriteCalls([`::set-output name=some output::false${os.EOL}`])
+  })
+
+  it('setOutput handles numbers', () => {
+    core.setOutput('some output', 1.01)
+    assertWriteCalls([`::set-output name=some output::1.01${os.EOL}`])
+  })
+
+  it('setFailed sets the correct exit code and failure message', () => {
     core.setFailed('Failure message')
     expect(process.exitCode).toBe(core.ExitCode.Failure)
     assertWriteCalls([`::error::Failure message${os.EOL}`])
   })
 
-  it('setFailure escapes the failure message', () => {
+  it('setFailed escapes the failure message', () => {
     core.setFailed('Failure \r\n\nmessage\r')
     expect(process.exitCode).toBe(core.ExitCode.Failure)
     assertWriteCalls([`::error::Failure %0D%0A%0Amessage%0D${os.EOL}`])
   })
 
+  it('setFailed handles Error', () => {
+    const message = 'this is my error message'
+    core.setFailed(new Error(message))
+    expect(process.exitCode).toBe(core.ExitCode.Failure)
+    assertWriteCalls([`::error::Error: ${message}${os.EOL}`])
+  })
+
   it('error sets the correct error message', () => {
     core.error('Error message')
     assertWriteCalls([`::error::Error message${os.EOL}`])
@@ -126,6 +153,12 @@ describe('@actions/core', () => {
     assertWriteCalls([`::error::Error message%0D%0A%0A${os.EOL}`])
   })
 
+  it('error handles an error object', () => {
+    const message = 'this is my error message'
+    core.error(new Error(message))
+    assertWriteCalls([`::error::Error: ${message}${os.EOL}`])
+  })
+
   it('warning sets the correct message', () => {
     core.warning('Warning')
     assertWriteCalls([`::warning::Warning${os.EOL}`])
@@ -136,6 +169,12 @@ describe('@actions/core', () => {
     assertWriteCalls([`::warning::%0D%0Awarning%0A${os.EOL}`])
   })
 
+  it('warning handles an error object', () => {
+    const message = 'this is my error message'
+    core.warning(new Error(message))
+    assertWriteCalls([`::warning::Error: ${message}${os.EOL}`])
+  })
+
   it('startGroup starts a new group', () => {
     core.startGroup('my-group')
     assertWriteCalls([`::group::my-group${os.EOL}`])
@@ -174,6 +213,16 @@ describe('@actions/core', () => {
     assertWriteCalls([`::save-state name=state_1::some value${os.EOL}`])
   })
 
+  it('saveState handles numbers', () => {
+    core.saveState('state_1', 1)
+    assertWriteCalls([`::save-state name=state_1::1${os.EOL}`])
+  })
+
+  it('saveState handles bools', () => {
+    core.saveState('state_1', true)
+    assertWriteCalls([`::save-state name=state_1::true${os.EOL}`])
+  })
+
   it('getState gets wrapper action state', () => {
     expect(core.getState('TEST_1')).toBe('state_val')
   })
diff --git a/packages/core/src/command.ts b/packages/core/src/command.ts
index 9bdfd9c41c..57067a1a52 100644
--- a/packages/core/src/command.ts
+++ b/packages/core/src/command.ts
@@ -2,8 +2,11 @@ import * as os from 'os'
 
 // For internal use, subject to change.
 
+// We use any as a valid input type
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
 interface CommandProperties {
-  [key: string]: string
+  [key: string]: any
 }
 
 /**
@@ -19,7 +22,7 @@ interface CommandProperties {
 export function issueCommand(
   command: string,
   properties: CommandProperties,
-  message: string
+  message: any
 ): void {
   const cmd = new Command(command, properties, message)
   process.stdout.write(cmd.toString() + os.EOL)
@@ -73,15 +76,28 @@ class Command {
   }
 }
 
-function escapeData(s: string): string {
-  return (s || '')
+/**
+ * Sanatizes an input into a string so it can be passed into issueCommand safely
+ * @param input input to sanitize into a string
+ */
+export function toCommandValue(input: any): string {
+  if (input === null || input === undefined) {
+    return ''
+  } else if (typeof input === 'string' || input instanceof String) {
+    return input as string
+  }
+  return JSON.stringify(input)
+}
+
+function escapeData(s: any): string {
+  return toCommandValue(s)
     .replace(/%/g, '%25')
     .replace(/\r/g, '%0D')
     .replace(/\n/g, '%0A')
 }
 
-function escapeProperty(s: string): string {
-  return (s || '')
+function escapeProperty(s: any): string {
+  return toCommandValue(s)
     .replace(/%/g, '%25')
     .replace(/\r/g, '%0D')
     .replace(/\n/g, '%0A')
diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
index 9072f46a79..85fc547a96 100644
--- a/packages/core/src/core.ts
+++ b/packages/core/src/core.ts
@@ -1,4 +1,4 @@
-import {issue, issueCommand} from './command'
+import {issue, issueCommand, toCommandValue} from './command'
 
 import * as os from 'os'
 import * as path from 'path'
@@ -33,11 +33,13 @@ export enum ExitCode {
 /**
  * Sets env variable for this action and future actions in the job
  * @param name the name of the variable to set
- * @param val the value of the variable
+ * @param val the value of the variable. Non-string values will be converted to a string via JSON.stringify
  */
-export function exportVariable(name: string, val: string): void {
-  process.env[name] = val
-  issueCommand('set-env', {name}, val)
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function exportVariable(name: string, val: any): void {
+  const convertedVal = toCommandValue(val)
+  process.env[name] = convertedVal
+  issueCommand('set-env', {name}, convertedVal)
 }
 
 /**
@@ -78,9 +80,10 @@ export function getInput(name: string, options?: InputOptions): string {
  * Sets the value of an output.
  *
  * @param     name     name of the output to set
- * @param     value    value to store
+ * @param     value    value to store. Non-string values will be converted to a string via JSON.stringify
  */
-export function setOutput(name: string, value: string): void {
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function setOutput(name: string, value: any): void {
   issueCommand('set-output', {name}, value)
 }
 
@@ -93,8 +96,9 @@ export function setOutput(name: string, value: string): void {
  * When the action exits it will be with an exit code of 1
  * @param message add error issue message
  */
-export function setFailed(message: string): void {
+export function setFailed(message: string | Error): void {
   process.exitCode = ExitCode.Failure
+
   error(message)
 }
 
@@ -119,18 +123,18 @@ export function debug(message: string): void {
 
 /**
  * Adds an error issue
- * @param message error issue message
+ * @param message error issue message. Errors will be converted to string via toString()
  */
-export function error(message: string): void {
-  issue('error', message)
+export function error(message: string | Error): void {
+  issue('error', message instanceof Error ? message.toString() : message)
 }
 
 /**
  * Adds an warning issue
- * @param message warning issue message
+ * @param message warning issue message. Errors will be converted to string via toString()
  */
-export function warning(message: string): void {
-  issue('warning', message)
+export function warning(message: string | Error): void {
+  issue('warning', message instanceof Error ? message.toString() : message)
 }
 
 /**
@@ -189,9 +193,10 @@ export async function group<T>(name: string, fn: () => Promise<T>): Promise<T> {
  * Saves state for current action, the state can only be retrieved by this action's post job execution.
  *
  * @param     name     name of the state to store
- * @param     value    value to store
+ * @param     value    value to store. Non-string values will be converted to a string via JSON.stringify
  */
-export function saveState(name: string, value: string): void {
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export function saveState(name: string, value: any): void {
   issueCommand('save-state', {name}, value)
 }