diff --git a/server/init.go b/server/init.go
index dabb1be40d48..b4e2e3fc525f 100644
--- a/server/init.go
+++ b/server/init.go
@@ -14,14 +14,29 @@ func GenerateCoinKey(algo keyring.SignatureAlgo) (sdk.AccAddress, string, error)
 	// generate a private key, with recovery phrase
 	info, secret, err := keyring.NewInMemory().NewMnemonic("name", keyring.English, sdk.GetConfig().GetFullBIP44Path(), keyring.DefaultBIP39Passphrase, algo)
 	if err != nil {
-		return sdk.AccAddress([]byte{}), "", err
+		return sdk.AccAddress{}, "", err
 	}
+<<<<<<< HEAD
 	return sdk.AccAddress(info.GetPubKey().Address()), secret, nil
+=======
+
+	addr, err := k.GetAddress()
+	if err != nil {
+		return nil, "", err
+	}
+
+	return addr, secret, nil
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 }
 
 // GenerateSaveCoinKey returns the address of a public key, along with the secret
 // phrase to recover the private key.
-func GenerateSaveCoinKey(keybase keyring.Keyring, keyName string, overwrite bool, algo keyring.SignatureAlgo) (sdk.AccAddress, string, error) {
+func GenerateSaveCoinKey(
+	keybase keyring.Keyring,
+	keyName, mnemonic string,
+	overwrite bool,
+	algo keyring.SignatureAlgo,
+) (sdk.AccAddress, string, error) {
 	exists := false
 	_, err := keybase.Key(keyName)
 	if err == nil {
@@ -30,23 +45,44 @@ func GenerateSaveCoinKey(keybase keyring.Keyring, keyName string, overwrite bool
 
 	// ensure no overwrite
 	if !overwrite && exists {
-		return sdk.AccAddress([]byte{}), "", fmt.Errorf(
-			"key already exists, overwrite is disabled")
+		return sdk.AccAddress{}, "", fmt.Errorf("key already exists, overwrite is disabled")
 	}
 
-	// generate a private key, with recovery phrase
+	// remove the old key by name if it exists
 	if exists {
-		err = keybase.Delete(keyName)
-		if err != nil {
-			return sdk.AccAddress([]byte{}), "", fmt.Errorf(
-				"failed to overwrite key")
+		if err = keybase.Delete(keyName); err != nil {
+			return sdk.AccAddress{}, "", fmt.Errorf("failed to overwrite key")
 		}
 	}
 
+<<<<<<< HEAD
 	info, secret, err := keybase.NewMnemonic(keyName, keyring.English, sdk.GetConfig().GetFullBIP44Path(), keyring.DefaultBIP39Passphrase, algo)
+=======
+	var (
+		record *keyring.Record
+		secret string
+	)
+
+	// generate or recover a new account
+	if mnemonic != "" {
+		secret = mnemonic
+		record, err = keybase.NewAccount(keyName, mnemonic, keyring.DefaultBIP39Passphrase, sdk.GetConfig().GetFullBIP44Path(), algo)
+	} else {
+		record, secret, err = keybase.NewMnemonic(keyName, keyring.English, sdk.GetConfig().GetFullBIP44Path(), keyring.DefaultBIP39Passphrase, algo)
+	}
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 	if err != nil {
-		return sdk.AccAddress([]byte{}), "", err
+		return sdk.AccAddress{}, "", err
 	}
 
+<<<<<<< HEAD
 	return sdk.AccAddress(info.GetPubKey().Address()), secret, nil
+=======
+	addr, err := record.GetAddress()
+	if err != nil {
+		return nil, "", err
+	}
+
+	return addr, secret, nil
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 }
diff --git a/server/init_test.go b/server/init_test.go
index d7439fe115f4..0b9aac658109 100644
--- a/server/init_test.go
+++ b/server/init_test.go
@@ -28,7 +28,7 @@ func TestGenerateSaveCoinKey(t *testing.T) {
 	kb, err := keyring.New(t.Name(), "test", t.TempDir(), nil)
 	require.NoError(t, err)
 
-	addr, mnemonic, err := server.GenerateSaveCoinKey(kb, "keyname", false, hd.Secp256k1)
+	addr, mnemonic, err := server.GenerateSaveCoinKey(kb, "keyname", "", false, hd.Secp256k1)
 	require.NoError(t, err)
 
 	// Test key was actually saved
@@ -49,15 +49,15 @@ func TestGenerateSaveCoinKeyOverwriteFlag(t *testing.T) {
 	require.NoError(t, err)
 
 	keyname := "justakey"
-	addr1, _, err := server.GenerateSaveCoinKey(kb, keyname, false, hd.Secp256k1)
+	addr1, _, err := server.GenerateSaveCoinKey(kb, keyname, "", false, hd.Secp256k1)
 	require.NoError(t, err)
 
 	// Test overwrite with overwrite=false
-	_, _, err = server.GenerateSaveCoinKey(kb, keyname, false, hd.Secp256k1)
+	_, _, err = server.GenerateSaveCoinKey(kb, keyname, "", false, hd.Secp256k1)
 	require.Error(t, err)
 
 	// Test overwrite with overwrite=true
-	addr2, _, err := server.GenerateSaveCoinKey(kb, keyname, true, hd.Secp256k1)
+	addr2, _, err := server.GenerateSaveCoinKey(kb, keyname, "", true, hd.Secp256k1)
 	require.NoError(t, err)
 
 	require.NotEqual(t, addr1, addr2)
diff --git a/simapp/simd/cmd/testnet.go b/simapp/simd/cmd/testnet.go
index 071d9364d0e2..975f03af9ff0 100644
--- a/simapp/simd/cmd/testnet.go
+++ b/simapp/simd/cmd/testnet.go
@@ -178,7 +178,7 @@ func InitTestnet(
 			return err
 		}
 
-		addr, secret, err := server.GenerateSaveCoinKey(kb, nodeDirName, true, algo)
+		addr, secret, err := server.GenerateSaveCoinKey(kb, nodeDirName, "", true, algo)
 		if err != nil {
 			_ = os.RemoveAll(outputDir)
 			return err
diff --git a/testutil/network/network.go b/testutil/network/network.go
index 2f17bca13273..1d66f92748fb 100644
--- a/testutil/network/network.go
+++ b/testutil/network/network.go
@@ -81,6 +81,7 @@ type Config struct {
 	TimeoutCommit    time.Duration              // the consensus commitment timeout
 	ChainID          string                     // the network chain-id
 	NumValidators    int                        // the total number of validators to create and bond
+	Mnemonics        []string                   // custom user-provided validator operator mnemonics
 	BondDenom        string                     // the staking bond denomination
 	MinGasPrices     string                     // the minimum gas prices each validator will accept
 	AccountTokens    sdk.Int                    // the amount of unique validator tokens (e.g. 1000node0)
@@ -264,13 +265,27 @@ func New(t *testing.T, cfg Config) *Network {
 		tmCfg.ProxyApp = proxyAddr
 
 		p2pAddr, _, err := server.FreeTCPAddr()
+<<<<<<< HEAD
 		require.NoError(t, err)
+=======
+		if err != nil {
+			return nil, err
+		}
+
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 		tmCfg.P2P.ListenAddress = p2pAddr
 		tmCfg.P2P.AddrBookStrict = false
 		tmCfg.P2P.AllowDuplicateIP = true
 
 		nodeID, pubKey, err := genutil.InitializeNodeValidatorFiles(tmCfg)
+<<<<<<< HEAD
 		require.NoError(t, err)
+=======
+		if err != nil {
+			return nil, err
+		}
+
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 		nodeIDs[i] = nodeID
 		valPubKeys[i] = pubKey
 
@@ -281,8 +296,26 @@ func New(t *testing.T, cfg Config) *Network {
 		algo, err := keyring.NewSigningAlgoFromString(cfg.SigningAlgo, keyringAlgos)
 		require.NoError(t, err)
 
+<<<<<<< HEAD
 		addr, secret, err := server.GenerateSaveCoinKey(kb, nodeDirName, true, algo)
 		require.NoError(t, err)
+=======
+		var mnemonic string
+		if i < len(cfg.Mnemonics) {
+			mnemonic = cfg.Mnemonics[i]
+		}
+
+		addr, secret, err := server.GenerateSaveCoinKey(kb, nodeDirName, mnemonic, true, algo)
+		if err != nil {
+			return nil, err
+		}
+
+		// if PrintMnemonic is set to true, we print the first validator node's secret to the network's logger
+		// for debugging and manual testing
+		if cfg.PrintMnemonic && i == 0 {
+			printMnemonic(l, secret)
+		}
+>>>>>>> b0190834c (feat: support custom mnemonics in in-process testing network (#10922))
 
 		info := map[string]string{"secret": secret}
 		infoBz, err := json.Marshal(info)